VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2023-02-04T22:22:28ZEPrintshttp://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/2022-10-26T21:59:36Z2022-10-26T21:59:36Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4758This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47582022-10-26T21:59:36ZElectrical measurement-type surface plasmon resonance sensor, Electrical measurement-type surface plasmon resonance sensor chip, and method for detecting change in surface plasmon resonanceAmrita SanaGiles AllisonHironoki SuzukiHidemi KatoMasao AndoViet Cuong Le2022-08-22T04:06:17Z2022-08-22T04:06:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4773This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47732022-08-22T04:06:17ZVortex particle method with iterative Brinkman penalization for simulation of flow past sharp-shape bodiesThis paper presents a Lagrangian vortex method combined with iterative Brinkman penalization for the simulation of incompressible flow past a complex geometry. In the proposed algorithm, particle and penalization domains are separately introduced. The particle domain is for the computation of particle convection and diffusion, while the penalization domain is the enforcement of the wall boundary conditions. In iterative Brinkman penalization, the no-slip boundary condition is enforced by applying penalization force in multiple times within each time step. This enables large time step size reducing computational cost and maintains the capability in handling complex geometries. The method is validated for benchmark problems such as an impulsively started flow past a circular cylinder, normal to a flat plate, and a symmetric airfoil at Reynolds numbers ranging from 550 to 1000. The vorticity and streamline contours, drag, and lift coefficients show a good agreement with those reported in literature.Dung Duong Vietduongdv@vnu.edu.vnZuhal Lavi Rizki2022-08-22T03:59:25Z2022-08-22T03:59:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4714This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47142022-08-22T03:59:25ZModified Savonius Wind Turbine for Wind Energy Harvesting in Urban EnvironmentsAnh Dinh Leanh.ld@vnu.edu.vnDuc Minh BanhHoang Van TamTran The Hung2022-08-22T03:58:26Z2022-08-22T03:58:26Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4755This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47552022-08-22T03:58:26ZVibration analysis of auxetic laminated plate with magneto-electro-elastic face sheets subjected to blast loadingDat Ngo Dinhdat.ngodinh@vnu.edu.vnQuan Tran QuocDuc Nguyen Dinhducnd@vnu.edu.vn2022-08-22T03:58:21Z2022-08-22T03:58:21Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4756This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47562022-08-22T03:58:21ZInvestigation of a sandwich plate with two MEE face sheets and FGM core layer from the nonlinear dynamic buckling point of viewA sandwich plate with two Magneto-Electro-Elastic (MEE) face sheets and Functionally Graded Materials (FGM) core layer resting on an elastic foundation and in a thermal environment will be studied in this paper for the nonlinear dynamic buckling problem. The hypothetical plate model above is formed from the fact that MEE materials have been receiving special attention from the research community owing to their specialized performance and coupled behavior under thermal, electric, magnetic, and mechanical loads, while FGM has been introducing for controlling material response to deformation, dynamic loading as well as to corrosion and wear, etc. The combination of these two materials in the sandwich plate model is expected to create a remarkable new sandwich model. The establishment of all basic equations for the nonlinear dynamic buckling problem of this novel sandwich model will be solved by analytical
methods, and the effects of geometrical parameters, temperature, electric and magnetic potentials on the nonlinear dynamic buckling of the sandwich plate will be shown in the numerical results of this study.Dinh Dat Ngodat.ngodinh@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vnDinh Giang VuThi Thuy Anh Vuanhvutt@vnu.edu.vn2022-08-22T03:58:16Z2022-08-22T03:58:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4754This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47542022-08-22T03:58:16ZNonlinear thermal dynamic buckling and global optimization of smart sandwich plate with porous homogeneous core and carbon nanotube reinforced nanocomposite layersDat Ngo DinhQuan Tran QuocDuc Nguyen Dinh2022-08-19T05:36:10Z2022-08-19T05:36:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4733This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47332022-08-19T05:36:10ZLow-Reynolds-number wake of three tandem elliptic cylindersThe flow around three elliptic cylinders with equal spacing and aspect ratio in tandem arrangements was numerically investigated through direct numerical simulation. The spacing ratio (L/D, where D and L are the major axis and the center-to-center distance of two adjacent elliptic cylinders, respectively) ranging from 1.5 to 10 and the Reynolds numbers ofDuong Viet Dungduongdv@vnu.edu.vnNguyen Van DucNguyen Van TienNgo Ich Long2022-08-19T05:35:42Z2022-08-19T05:35:42Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4729This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47292022-08-19T05:35:42ZDesign of a low-cost pressure measurement device: validation and testingTran The HungNguyen DungAnh Dinh Leanh.ld@vnu.edu.vn2022-03-21T00:42:18Z2022-03-21T00:42:18Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4698This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46982022-03-21T00:42:18ZApplication of RANS turbulence model in simulation base flow of axisymmetric body in wide range of Mach numberTran The HungDao Cong TruongDo Van MinhNguyen Minh TrangPham ChungAnh Dinh Leanh.ld@vnu.edu.vn2022-03-21T00:37:58Z2022-03-21T00:37:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4716This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47162022-03-21T00:37:58ZThe Influence of Spike-Nosed Length on Aerodynamic Drag of a Wing-Projectile ModelTran The HungAnh Dinh Leanh.ld@vnu.edu.vnDao Minh2022-03-21T00:32:31Z2022-03-21T00:32:31Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4715This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/47152022-03-21T00:32:31ZAssessment of Flow Fluctuation Pressure Models for Simulating the Cavitating FlowAnh Dinh Leanh.ld@vnu.edu.vnLinh Ngoc LeAnh Viet TruongHung The Tran2021-12-13T03:55:43Z2021-12-13T03:55:43Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4651This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46512021-12-13T03:55:43ZEffect of the Elliptical Shape on the Performance of the Modified Savonius Wind TurbineMinh Duc BanhAnh Dinh Leanh.ld@vnu.edu.vn2021-12-13T03:54:40Z2021-12-13T03:54:40Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3623This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36232021-12-13T03:54:40ZA simplified thermodynamic effect model for cavitating flow in hot waterAnh Dinh Leanh.ld@vnu.edu.vnIga Yuka2021-12-13T03:54:17Z2021-12-13T03:54:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3624This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36242021-12-13T03:54:17ZExperimental and Numerical Study of Hot Water Cavitation on a NACA0015 HydrofoilAnh Dinh Leanh.ld@vnu.edu.vnYuka Igaiga@cfs.ifs.tohoku.ac.jp2021-12-13T03:53:25Z2021-12-13T03:53:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4652This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46522021-12-13T03:53:25ZNummerical Analysis on Lift and Drag of a Finite-thickness Circular Arc Hydrofoil in Different CamberThanh Quang NguyenAnh Dinh Leanh.ld@vnu.edu.vnAnh Viet Truong2021-12-13T03:52:54Z2021-12-13T03:52:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4650This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46502021-12-13T03:52:54ZNumerical study for flow behavior and drag of axisymmetric boattail models at different Mach numberHung The TranTruong Cong DaoAnh Dinh Leanh.ld@vnu.edu.vnTrang Minh Nguyen2021-12-10T10:58:19Z2021-12-10T10:58:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4661This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46612021-12-10T10:58:19ZMAI_ARM: Robot Tay Máy Thông Minh sử dụng Trí tuệ nhân tạo Đa thể thứcCác hệ thống robot tay máy đóng một vai trò rất quan trọng trong sản xuất công nghiệp hiện đại. Việc ứng dụng robot tay máy trong đời sống hàng ngày sẽ giúp ích con người rất nhiều, ví dụ như tự động hóa hoàn toàn quy trình phân phát thuốc và thực phẩm cho bệnh nhân nhiễm COVID-19. Ứng dụng robot tay máy trong đời sống đòi hỏi một cách thức giúp người dùng dễ dàng tương tác với robot. Trong bài báo này, một phương pháp tương tác với robot tay máy sử dụng trí tuệ nhân tạo đa thể thức kết hợp giọng nói-hình ảnh được xây dựng. Bài báo cũng đề xuất phương pháp Chessboard Calibration giúp nâng cao độ chính xác trong việc xác định vị trí thực thi của robot tay máy. Một robot tay máy 4 bậc tự do (4-DOF) chế tạo bằng phương pháp in 3D sẽ được sử dụng để thực thi và đánh giá mô hình trí tuệ nhân tạo đa thể thức xây dựng được. Kết quả thực thi hệ thống được ghi hình và trình bày tại: https://youtu.be/RHgAyHXMH6IBao Minh Dinhminhdinh@vnu.edu.vnDuc Son Trantransonhhc12c5@gmail.comThe Huong Nguyenhuongrbe@gmail.comNam Dodonam.2801@gmail.comMinh Hoang Lelhoang17062000@gmail.comVan Xiem Hoangxiemhoang@vnu.edu.vn2021-12-10T10:58:14Z2021-12-10T10:58:14Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4660This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46602021-12-10T10:58:14ZĐánh Giá và Tối Ưu Thuật Toán Hector SLAM Ứng Dụng Lập Bản Đồ và Định Vị Trên Pimouse RobotLập bản đồ và định vị là hai trong bốn bài toán cơ bản của hệ thống Robot di động. Hai cách tiếp cận phổ biến hiện nay để giải quyết bài toán này là sử dụng hệ thống LiDAR hoặc/và hệ thống cảm biến hình ảnh cùng các thuật toán xử lý dữ liệu thu được. Hướng tiếp cận với LiDAR và thuật toán Hector SLAM cho kết quả tạo bản đồ với độ chính xác cao, nhưng đòi hỏi phải tối ưu các tham số của thuật toán. Để hiểu rõ vấn đề này, chúng tôi nghiên cứu và đánh giá các tham số chính ảnh hưởng tới hiệu năng thực thi của thuật toán Hector SLAM cho một hệ thống Robot di động sử dụng LIDAR để lập bản đồ và định vị. Hiệu năng của hệ thống được đánh giá trên hai khía cạnh: i) chất lượng của bản đồ thu được và ii) lượng CPU chiếm dụng. Với việc hiểu rõ ảnh hưởng của các tham số của thuật toán Hector SLAM tới hiệu năng của hệ thống, người dùng có thể thay đổi linh hoạt các tham số này tùy vào Robot sử dụng. Kết quả nghiên cứu được minh họa trên một hệ thống Robot di động được phát triển bởi công ty RT corporation, Nhật bản, Pimouse Robot.Bao Minh Dinhminhdinh@vnu.edu.vnAnh Viet Dangvietda@vnu.edu.vnCanh Thanh Nguyencanhthanhlt@gmail.comVan Xiem Hoangxiemhoang@vnu.edu.vn2021-12-10T10:55:34Z2021-12-10T10:55:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4632This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46322021-12-10T10:55:34ZStudy of Thermodynamic Effect on the Mechanism of Flashing Flow under Pressurized Hot Water by a Homogeneous ModelAnh Dinh Leanh.ld@vnu.edu.vn2021-11-27T02:35:34Z2021-11-27T02:35:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4596This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45962021-11-27T02:35:34ZBoundary Measurement for Axisymmetric Blunt Base Body by Numerical nd Experimental MethodsHung The TranAnh Dinh Leanh.ld@vnu.edu.vnTrang Minh NguyenTruong Cong Dao2021-11-27T02:35:16Z2021-11-27T02:35:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4628This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46282021-11-27T02:35:16ZEffect of the Mesh Types on the Prediction of Flow Aerodynamic around AirfoilAnh Dinh Leanh.ld@vnu.edu.vnHoang Van Tam2021-11-27T02:35:03Z2021-11-27T02:35:03Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4631This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46312021-11-27T02:35:03ZImprovement of Mass Transfer Rate Modeling for Prediction of Cavitating FlowAnh Dinh Leanh.ld@vnu.edu.vnTran The Hung2021-11-27T02:34:37Z2021-11-27T02:34:37Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4630This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46302021-11-27T02:34:37ZExperimental study of the skin-friction topology around the Ahmed body in cross-wind conditionTran The HungAnyoji MasayukiNakashima TakujiShimizu KeigoAnh Dinh Leanh.ld@vnu.edu.vn2021-11-27T02:32:29Z2021-11-27T02:32:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4649This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46492021-11-27T02:32:29ZNumerical Simulation of Hot Water Flashing Flow in a Converging - Diverging NozzleAnh Dinh Leanh.ld@vnu.edu.vnQuan Hoang NguyenLong Ich NgoAnh Viet TruongJunnosuke OkajimaYuka Iga2021-11-09T09:38:01Z2021-12-09T09:37:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4635This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46352021-11-09T09:38:01ZTowards Vision-based Concrete Crack Detection: Automatic Simulation of Real-world CracksRecently, automatic pavement crack detection using computer vision has attracted great attention from many research groups globally. One of the major concerns in this field, especially for deep learning-based approaches, is data collection, where human resources, time, and space are essential factors. This process remains a challenging task and significantly influences the results of crack detection algorithms, particularly when applied to large infrastructures such as bridges, dams, and high-rise buildings. This study aims to combine the synthesis of knowledge from fracture mechanics, simulation, machine learning, and research on concrete crack propagation to simulate crack propagation. Based on the simulation results, mathematical models of simulated crack will be generated using machine learning. Experimental results have been conducted on various reputable crack image datasets, showing a high correlation between the simulated cracks and the real-world ones. This novel, interdisciplinary approach is expected to have many useful points for a research area where data collection and labeling are still facing many difficulties.Tran Hiep Dinhtranhiep.dinh@vnu.edu.vnThi Thuy Anh Vuanhvutt@vnu.edu.vnTruongGiang Nguyenntgiang@imech.vast.vnCong Hieu Le18020508@vnu.edu.vnLinh Trung Nguyenlinhtrung@vnu.edu.vnNguyen Dinh Ducducnd@vnu.edu.vnChin-Teng Linchin-teng.lin@uts.edu.au2021-10-31T00:46:16Z2021-10-31T00:46:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4592This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45922021-10-31T00:46:16ZNumerical simulation of water flashing flow of hot water in a converging-diverging nozzleAnh Dinh Leanh.ld@vnu.edu.vnLong Ich NgoAnh Viet TruongOkajima JunnosukeYuka Iga2021-10-31T00:46:00Z2021-10-31T00:46:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4590This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45902021-10-31T00:46:00ZExperimental and Numerical Evaluation of a Simplified Thermodynamic Model for NACA0015 Hydrofoil Cavitation in Hot WaterAnh Dinh Leanh.ld@vnu.edu.vn2021-10-31T00:45:47Z2021-10-31T00:45:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4559This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45592021-10-31T00:45:47ZStudy of Thermodynamic Effect on the Mechanism of Flashing Flow under Pressurized Hot Water by a Homogeneous ModelThe flashing flow in a Moby_Dick converging-diverging nozzle under pressurized hot water from 460.5 K to 483.5 K is simulated using a homogeneous compressible water-vapor two-phase flow model. The kinematic and thermodynamic mass transfer are accessed using the cavitation model based on the Hertz-Knudsen-Langmuir equation. Our simplified thermodynamic model is coupled with the governing equations to capture the phase-change heat transfer. This numerical method proved its reliability through a comparison with available experimental data of flow parameters inside the nozzle. Consequently, the present numerical method shows good potential for simulating the flashing flow under pressurized hot water conditions. The satisfying prediction of averaged flow parameters with a slight improvement compared to reference numerical data is reproduced. The results confirm a noticeable impact of the thermodynamic effect on the mechanism of flashing flow, resulting in a considerable decrease in the flow temperature and the saturated vapor pressure. The flashing non-equilibrium is significantly decreased, forcing the flashing flow to be classified as the usual cavitation behavior and better suited to homogeneous model. While the temperature drop is highly dependent on evaporation, the thermodynamic suppression is influenced by the condensation. The suppression effect, unobserved in water at a lower temperature in previous studies, is noticeable for the pressurized hot water flow characterized by the cavitation mechanism. The vapor void fraction decreased considerably in the radial and axial directions as the water temperature rose to 483.5 K in this study.Anh Dinh Leanh.ld@vnu.edu.vn2021-10-31T00:45:14Z2021-10-31T00:45:14Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4606This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46062021-10-31T00:45:14ZĐÁNH GIÁ HIỆU QUẢ TÍNH TOÁN CỦA SÁU SỐ MÔ HÌNH RỐI MÔ PHỎNG DÒNG CHẢY BAO BIÊN DẠNG NACA4412 TẠI SỐ RE 1x106Vấn đề nghiên cứu tìm ra mô hình rối phù hợp để dự báo đặc tính khí động học profile cánh tại một điều kiện dòng vào cụ thể (số Reynolds và dải góc ấn) là rất quan trọng, quyết định đến độ tin cậy của kết quả nghiên cứu. Trong nghiên cứu này, Sáu mô hình rối được áp dụng để mô phỏng dòng chảy bao biên dạng NACA4412. Kết quả tính toán được so sánh với kết quả thực nghiệm tại dải góc tấn −90 ≤Thanh Văn NguyenAnh Dinh Leanh.ld@vnu.edu.vnAnh Viet Truong2021-10-31T00:44:02Z2021-10-31T00:44:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4627This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46272021-10-31T00:44:02ZImprovement of Mass Transfer Rate Modeling for Prediction of Cavitating FlowAnh Dinh Leanh.ld@vnu.edu.vnHung The Tran2021-10-31T00:42:10Z2021-10-31T00:42:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4611This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/46112021-10-31T00:42:10ZCharacteristics of the flow around four cylinders of various shapesNguyen Van Lucnguyenvanluc@tdtu.edu.vnTrung Nguyen-ThoiDuong Viet Dungduongdv@vnu.edu.vn2021-10-31T00:41:45Z2021-10-31T00:41:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4599This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45992021-10-31T00:41:45ZExperimental study of the skin-friction topology around the Ahmed body in cross-wind conditionTran The HungAnyoji MasayukiNakashima TakujiShimizu KeigoAnh Dinh Leanh.ld@vnu.edu.vn2021-10-31T00:41:12Z2021-10-31T00:41:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4495This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/44952021-10-31T00:41:12ZNghiên cứu biên dạng cánh cải thiện hiệu suất tuabin gió
Savonius bằng công cụ CFDDuc Minh BanhVan Tam HoangAnh Dinh Leanh.ld@vnu.edu.vn2021-10-31T00:41:00Z2021-10-31T00:41:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4494This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/44942021-10-31T00:41:00ZMô phỏng dòng xâm thực hơi và xâm thực khí bằng phương
pháp mô hình đồng nhất cho dòng không nhớtNgoc Linh LeDai Viet TranVan Duc NguyenAnh Dinh Leanh.ld@vnu.edu.vn2021-10-31T00:40:05Z2021-10-31T00:40:05Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3621This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36212021-10-31T00:40:05ZNumerical simulation study of cavitation in liquefied hydrogenAnh Dinh Leanh.ld@vnu.edu.vnJunnosuke OkajimaYuka Iga2021-06-28T02:37:54Z2021-06-28T02:37:54Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4535This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45352021-06-28T02:37:54ZOptimizing linear generator design’s parameters for output power using mix numerical and analytical techniquePermanent magnet linear devices have wide
applications in various fields. In the field of wave energy
conversion, the use of linear generator has earlier been regarded
as difficult and uneconomical due to technical problems.
Researches on wave energy converters have been carried out,
but the conversion efficiency is still limited. Studies of the
magnetic field of a linear generator have shown the ability to
significantly improve performance when using the Halbach
array magnets structure. In this study, a mixed numerical and
analytical technique is presented to optimize linear generator
design’s parameters for wave energy converter power
performance. At first, numerical method used for maximize of
magnetic field’s strength inside linear generator. Then, a
matlab-simulink program use the simulated magnetic field
result to optimize the power of the linear generator.Huy Diep Dodiepdh@vnu.edu.vnVan Duc NguyenXuan Quynh Nguyenquynhctm@gmail.comThe Ba Dangbadt@vnu.edu.vn2021-06-28T02:07:10Z2021-06-28T02:07:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4505This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45052021-06-28T02:07:10ZKhảo sát từ trường của dãy nam châm kép sắp xếp theo cấu trúc Halbach trong máy phát tuyến tính sử dụng trong thiết bị chuyển đổi năng lượng sóngCác thiết bị máy tuyến tính sử dụng nam châm vĩnh cửu có ứng dụng rộng rãi trong các lĩnh vực khác nhau. Trong lĩnh vực chuyển đổi năng lượng sóng, việc sử dụng máy phát tuyến tính trước đây được coi là khó khăn và không kinh tế do gặp nhiều vấn đề về mặt kỹ thuật. Nhiều nỗ lực nghiên cứu đã được thực hiện để vượt qua những khó khăn đó, tuy nhiên kết quả thực tế vẫn còn nhiều hạn chế. Trong nghiên cứu này, nỗ lực cải thiện mật độ từ thông trong máy phát tuyến tính đã được thực hiện. Cấu trúc dãy nam châm kép Halbach được khảo sát theo các thông số kích thước của máy phát điện trong thiết bị chuyển đổi năng lượng sóng nhằm tăng cường mật độ từ thông trong khe hở không khí, từ đó chọn lựa các thông số hợp lý để cải thiện hiệu suất đầu ra của máy phát điện tuyến tính. Kết quả số từ phương pháp phần tử hữu hạn được sử dụng để mô phỏng và quan sát phân phối từ thông trong máy. Kết quả cũng cho thấy việc sử dụng nam châm cấu trúc Halbach kép đã tăng mật độ từ thông so với thiết bị sử dụng cấu trúc nam châm thông thường.Huy Diep Dodiepdh@vnu.edu.vnVan Duc NguyenXuan Quynh NguyenThe Ba Dangbadt@vnu.edu.vn2021-06-28T00:14:29Z2021-06-28T00:14:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4503This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/45032021-06-28T00:14:29ZỨng dụng Matlab-Simulink trong tính toán suất điện động và công suất cho máy phát điện tịnh tiến sử dụng cấu trúc nam châm HalbachNăng lượng sạch và năng lượng tái tạo là xu hướng và nhu cầu phát triển tất yếu của mọi quốc gia. Năng lượng sóng biển là một trong số đó và Việt Nam có tiềm năng thế mạnh lớn khi có đường bờ biển dài bao quanh. Các nghiên cứu về thiết bị chuyển đổi năng lượng sóng đã được thực hiện, tuy nhiên hiệu suất chuyển đổi vẫn còn hạn chế. Những nghiên cứu về trường từ trong lòng máy phát điện tịnh tiến đã cho thấy khả năng cải thiện hiệu suất đáng kể khi sử dụng cấu trúc nam châm dãy Halbach. Những tính toán về từ trường tĩnh, quá trình chuyển đổi từ năng lượng từ sang năng lượng điện đòi hỏi nhiều công sức và thời gian. Bài báo trình bày những kết quả nghiên cứu về mô hình hóa và mô phỏng của hệ điện từ bằng việc ứng dụng Matlab-Simulink. Kết quả nghiên cứu này có thể được sử dụng trong nghiên cứu đặc trưng, thông số hoạt động máy phát điện tuyến tínhHuy Diep Dodohuydiep@gmail.comVan Duc NguyenThe Ba Dangbadt@vnu.edu.vn2021-05-31T11:03:51Z2021-05-31T11:03:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4444This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/44442021-05-31T11:03:51ZAssessment of a Homogeneous Model for Simulating a Cavitating Flow in Water under a Wide Range of TemperaturesThe cavitating flow on a NACA0015 hydrofoil in water under a wide range of temperatures is simulated with or without non-condensation gas using a homogeneous model. Our simplified thermodynamic model is coupled with governing equations to capture the latent heat transfer in cavitation. A numerical evaluation proves its applicability through a comparison with experimental data. As a result, the numerical evaluation illustrates good agreement with measured data for both simulations with or without non-condensation gas. The expected prediction pressure coefficient is in better agreement with experimental data for high-temperature water compared to the existing numerical data. Although the temperature depression inside the cavity is confirmed numerically, the thermodynamic effect shows a weak impact on the cavitation behavior near the boiling temperature (100oC). The cavitating flow can therefore be simulated reasonably by an iso-thermal approach at a reasonable cost. The suppression of the void fraction as the water temperature increases is deduced by the flow behavior rather than the thermodynamic effect. Finally, the impact of a non-condensation gas is closely linked to the thermodynamic properties of the water and the flow behavior. The attached cavity position shifts closer to the hydrofoil leading edge significantly in high-temperature water, while an identical position is reproduced for room temperature conditions in comparison with the simulation without a non-condensation gas.Anh Dinh Leanh.ld@vnu.edu.vn2021-05-31T11:03:34Z2021-05-31T11:03:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4448This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/44482021-05-31T11:03:34ZUnsteady Vortex Dynamics of Two-Dimensional Pitching Flat Plate Using Lagrangian Vortex MethodVortex dynamics of wakes generated by two-dimensional rectan-gular pitching flat plates in free stream are examined with directnumerical simulation using Lagrangian vortex method. The devel-oped method simulates external flow around complex geometryby tracking local velocities and vorticities of particles, introducedwithin the fluid domain. The viscous effect is modeled using acore spreading method coupled with the splitting and merging spa-tial adaptation scheme. The particle’s velocity is calculated usingBiot-Savart formulation. To accelerate computation, Fast MultipoleMethod (FMM) is employed. The solver is validated by perform-ing an impulsively started cylinder at Reynolds number 550. Theresults of the computation have reasonable agreement with refer-ences listed in literature. For the vortex dynamics of pitching flatplate, the detaching LEV creates a remarkable peak in the lift forcebefore the end of motion for the different pitching cases. For thelow Reynolds number, force generated by the pitching flat plateis fairly independent of Reynolds numbers. The current studiesalso observed that TEV produced at higher Reynolds number has astronger suction than that at smaller Reynolds numbers.Duong Viet Dungduongdv@vnu.edu.vnZuhal Lavi RizkiMuhammad Hari2021-05-31T11:03:11Z2021-05-31T11:03:11Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4447This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/44472021-05-31T11:03:11ZFluid–structure coupling in time domain for dynamic stall using purely Lagrangian vortex methodThis paper presents the purely fast Lagrangian vortex method (FLVM) for the simulation of the external incompressible flows past heaving and pitching bodies with high-frequency oscillation. The Nascent vortex element is introduced to the flow field to retain the Lagrangian characteristics of the solver. The viscous effect is modeled using a core spreading method coupled with the splitting and merging spatial adaptation scheme. The particle’s velocity is calculated using Biot–Savart formulation. To accelerate computation, a fast multipole method (FMM) is employed. The validity of FLVM solver is verified by temporal and spatial convergence studies for the case of flows past an impulsively started cylinder at the Reynolds numbers ranging from 50 to 9500. The accuracy of FLVM is then confirmed for the simulation of flows around the pitching flat plate and oscillating airfoil. The time history of drag and lift coefficients and the vorticity contours show a good agreement with those reported in literature. Furthermore, the FLVM is employed to determine the flutter derivatives and flutter speed of an oscillating flat plate. Results are compared with theoretical solutions based on Theodorsen’s function. In general, the results agree well with those obtained by the inviscid theory.Duong Viet Dungduongdv@vnu.edu.vnZuhal Lavi RizkiMuhammad Hari2021-05-31T11:01:47Z2021-05-31T11:01:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4446This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/44462021-05-31T11:01:47ZTurbulence cascade model for viscous vortex ring-tube reconnectionThe reconnection of a vortex ring and a vortex tube in a viscous fluid with the effects of two vortex core sizes (σ 0 = 0.12r 0 and 0.24r 0 , where r 0 are initial ring radius) and three initial flow configurations (left-offset, center and right-offset) at Reynolds number (Re Γ) of 10000 was investigated using a high-order Vortex-in-cell method combined with a Large-eddy simulation model. For the left-offset case, a large part of the ring, slipping over the tube, associates with a small part of the tube to establish a new vortex ring, whereas the rest of the tube is reconnected by another part of the ring. For the center case, half of the ring joins with a part of the tube to construct an elliptical vortex ring while the rest connects because of viscosity. The reconnected ring and tube become more stable and are like the initial ones in the ultimate stage. For the right-offset case, both the ring and tube's reconnection occurs, and the reconnected elliptical vortex ring is rapidly distorted. The proportion of reconnected ring increases, and then this ring section loses its integrity, decaying into a complex cluster of various-scales vortex structures in different shapes. At σ 0 = 0.12r 0 , the secondary vortex structures surrounding the tube and ring appear in three cases, while they are only observed for the center case at σ 0 = 0.24r 0. For three flow configurations and two vortex core sizes, after the reconnection, the energy cascade of the flow approaches a k −5/3 slope of Kolmogorov's similarity hypotheses and a k −3 slope in the ranges of wavenumbers (k) from 3 to 10 and from 10 to 40, respectively. The highest population of small-scale coherent vortex structures is observed for the right-offset, followed by the center and left-offset. In addition, a larger number of these structures were observed for a smaller core size. This validates that the mixing performance is the best at a small vortex core and in the right-offset configuration.Duong Viet Dungduongdv@vnu.edu.vnNguyen Van DucNguyen Van Lucnguyenvanluc@tdtu.edu.vn2021-03-24T04:48:56Z2021-03-24T04:48:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4395This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43952021-03-24T04:48:56ZVortex ring-tube reconnection in a viscous fluidThe vortex ring-tube reconnection in a viscous fluid was investigated using a proposed vortex-in-cell method combined with a large eddy simulation model (LVIC). This method was verified using simulations of the Taylor–Green vortex flow at the Reynolds numbers (Re) 200 and 2000. The results show that the present method can capture the small-scale vortex structures in turbulent flows well. Besides, a Lagrangian method for passive scalar transport was successfully developed to track the vortex dynamics. The LVIC was then applied to three simulations of the interaction of a vortex ring at RerΓ(Γ/ν)=10000 and a vortex tube at RetΓ=1000, 5000, and 10 000. At RerΓ=10000 and RetΓ=1000, the effects of the tube on the ring are trivial while the ring breaks it into two parts and entrains them. The flow’s energy spectrum remains unchanged with time, the small-scale vortices are not generated, and the ring’s motion plays a key role in the flow. Moreover, the helicity distribution on the vortices is negligible. At RerΓ=10000 and RetΓ=5000, the tube breaks into two parts, and the leaving part of the tube interacts forcefully with the ring to form the small-scale vortices at the high wavenumbers. The population of small-scale vortex structures increases with time, and the large-scale vortices are twisted after the impingement. At RerΓ=10000 and RetΓ=10000, the impingement of the ring on the tube leads to their breakdown and reconnection. A part of the ring interacts with the leaving part of the tube to form a secondary ring, while the rest replaces the leaving part to reconnect the tube. The population of small-scale vortex structures and helicity distribution increase in this flow stage because of the interaction of the secondary ring wake and connection vortices. However, after the reconnection, the population and helicity distribution on the vortex structures significantly decrease. The smallest-scale vortex structure and the most effective mixing occur with RerΓ=10000 and RetΓ=5000.Nguyen Van Lucnguyenvanluc@tdtu.edu.vnDuong Viet Dungduongdv@vnu.edu.vn2021-01-06T02:43:57Z2021-01-06T02:43:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4363This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43632021-01-06T02:43:57ZNonlinear dynamic response and vibration of imperfect eccentrically stiffened sandwich third-order shear deformable FGM cylindrical panels in thermal environmentshis study follows an analytical approach to investigate the nonlinear dynamic response and vibration of eccentrically stiffened sandwich functionally graded material (FGM) cylindrical panels with metal–ceramic layers on elastic foundations in thermal environments. It is assumed that the FGM cylindrical panel is reinforced by the eccentrically longitudinal and transversal stiffeners and subjected to mechanical and thermal loads. The material properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution. Based on the Reddy’s third-order shear deformation shell theory, the motion and compatibility equations are derived taking into account geometrical nonlinearity and Pasternak-type elastic foundations. The outstanding feature of this study is that both FGM cylindrical panel and stiffeners are assumed to be deformed in the presence of temperature. Explicit relation of deflection–time curves and frequencies of FGM cylindrical panel are determined by applying stress function, Galerkin method and fourth-order Runge-Kutta method. The influences of material and geometrical parameters, elastic foundations and stiffeners on the nonlinear dynamic and vibration of the sandwich FGM panels are discussed in detail. The obtained results are validated by comparing with other results in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoTran PhuongQuoc Quan TranVan Thanh Nguyen2020-12-04T08:26:24Z2020-12-04T08:26:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4121This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/41212020-12-04T08:26:24ZStatic Bending Analysis of Auxetic Plate by FEM and a New Third-Order Shear Deformation Plate Theoryn this paper, a finite element method (FEM) and a new third-order shear deformation plate theory are proposed to investigate a static bending model of auxetic plates with negative Poisson’s ratio. The three – layer sandwich plate is consisted of auxetic honeycombs core layer with negative Poisson’s ratio integrated, isotropic homogeneous materials at the top and bottom of surfaces. A displacement-based finite element formulation associated with a novel third-order shear deformation plate theory without any requirement of shear correction factors is thus developed. The results show the effects of geometrical parameters, boundary conditions, uniform transverse pressure on the static bending of auxetic plates with negative Poisson’s ratio. Numerical examples are solved, then compared with the published literatures to validate the feasibility and accuracy of proposed analysis method.Hong Cong PhamMinh Phuc PhamThi Thiem HoangTuan Manh DuongDinh Duc Nguyenducnd@vnu.edu.vn2020-12-04T08:26:07Z2020-12-04T08:26:07Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4120This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/41202020-12-04T08:26:07ZOptimization of Laminated Composite Plates for Maximum Biaxial Buckling LoadThis paper proposes an optimization procedure for maximization of the biaxial buckling load of laminated composite plates using the gradient-based interior-point optimization algorithm. The fiber orientation angle and the thickness of each lamina are considered as continuous design variables of the problem. The effect of the number of layers, fiber orientation angles, thickness and length to thickness ratios on the buckling load of the laminated composite plates under biaxial compression is investigated. The effectiveness of the optimization procedure in this study is compared with previous works.Dinh Nguyen Phamnguyenpd@vnu.edu.vnVu Quang-VietPapazafeiropoulos GeorgeThi Thiem HoangMinh Vuong PhamDinh Duc Nguyenducnd@vnu.edu.vn2020-04-24T07:37:21Z2020-04-24T07:37:21Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3953This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/39532020-04-24T07:37:21ZVibration and nonlinear dynamic response of imperfect sandwich piezoelectric auxetic plateQuoc Quan TranMinh Anh VuVinyas MaheshDinh Duc Nguyenducnd@vnu.edu.vn2019-12-26T11:03:34Z2019-12-26T11:03:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3903This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/39032019-12-26T11:03:34ZMô phỏng hoạt động của giếng trong khai thác dầu.Ngoc Hai DuongThe Ba Dangbadt@vnu.edu.vn2019-12-26T11:03:13Z2019-12-26T11:03:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3902This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/39022019-12-26T11:03:13ZMô phỏng dòng chảy ba pha dầu-nước-khí trong vỉa nứt nẻ tự nhiên.The Ba Dangbadt@vnu.edu.vnNgoc Hai Duong2019-12-26T11:02:57Z2019-12-26T11:03:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3901This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/39012019-12-26T11:02:57ZXác định thông số vỉa dầu theo lịch sử khai thác trên cơ sở phương pháp Gauss-Newton sửa đổiThe Ba Dangbadt@vnu.edu.vn2019-12-26T11:02:51Z2019-12-26T11:02:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3900This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/39002019-12-26T11:02:51ZNumerical Simulation of a Wave Energy Converter Using Linear Generator.The Ba Dangbadt@vnu.edu.vn2019-12-26T11:02:27Z2019-12-26T11:02:46Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3896This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38962019-12-26T11:02:27ZNumerical Model of Three Phase-Three Dimensional Flow in Porous Media for Reservoir Simulation.The Ba Dangbadt@vnu.edu.vnNgoc Hai Duong2019-12-26T11:01:04Z2019-12-26T11:08:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3895This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38952019-12-26T11:01:04ZDesign and Simulation of a vertical axis wind turbine
for using on navigational buoysAt present, wind turbine is mainly designed in two forms: vertical and horizontal axis turbines. However, they cannot be installed on navigational buoys because of disadvantages such as difficulty in balancing and easily damaging when colliding with external objects. A vertical axis wind turbine for navigation buoys has been developed. The report presents the structure development, simulation and design of a vertical axis wind turbines suitable for navigation buoys. This device can also be developed appropriately located in many location in the city to provide electricity to households or offices in a simple, portable and still safe way.The Ba Dangbadt@vnu.edu.vnHuy Diep Dodohuydiep@gmail.comHai Yen PhamVan Duc Nguyen2019-12-26T11:00:57Z2019-12-26T11:08:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3894This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38942019-12-26T11:00:57ZDesign Of Linear Generator With Halbach Dual Magnet Structure According To Wave Energy Converter For Navigational BuoysOperating equipments on river and sea require power but the supply conditions are usually difficult. With the characteristics of continuous operation, the navigational buoys need a stable and active power supply. The report presents the results of constructing structural design, operational modeling and simulation models to calculate the operation of wave energy converter for supplying power to navigational buoys. Simulation calculations were performed to test the device model and performance. The magnetic field in the linear generator is modeled according to the conventional magnet arrangement and the dual Halbach structure, thereby showing the advantage of the Halbach dual magnet array. The program was used to calculate and determine the construction parameters for actual design, manufacturing and testing of equipment in the next studyHuy Diep DoThe Ba Dangbadt@vnu.edu.vnVan Duc Nguyen2019-12-24T04:52:18Z2019-12-24T04:53:28Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3906This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/39062019-12-24T04:52:18ZStudy of Vibration of Dual-Buoy on the Linear Electrical Generator for Wave Energy ConverterToday, Ocean wave energy is a renewable energy source with a large potential to contribute to the world’s electricity
production. This report presents the results on the modeling and optimization the systems of two buoys for wave energy converter. The
first is a floater. The second is a semi-submerged body. The energy is converted from the relative motion between the two buoys by the
linear generator. For simulation in three dimensions, the system of equations (6 modes of motions) has been obtained. The governing
equations are solved by ANSYS AQWA software and Matlab tools. In this report, Response Amplitude Operators (RAOs) are analysed.
Based on the RAOs results, we will determine the wave frequency domain for the maximum energy. The obtained results can be used for
the simulation, calculation and geometry optimization of the more realistic system in wave energy convertion.Nguyen Hoang Quannhquan@vnu.edu.vnThanh Tung Trantranthanhtung@vnu.edu.vn2019-12-24T04:51:18Z2019-12-24T04:51:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3893This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38932019-12-24T04:51:18ZTính toán và tối ưu hóa thiết kế máy phát điện dãy nam châm Halback cho thiết bị chuyển đổi năng lượng sóngMáy phát tịnh tiến có cấu tạo thích hợp cho phát triển các thiết bị chuyển đổi năng lượng sóng cơ cấu trực tiêp. Tuy nhiên, do cơ cấu trực tiếp thường sinh ra chuyển động tương đối không lớn giữa roto và stator, vì vậy gây khó khăn trong thiết kế để nâng cao sức điện động máy phát cũng như nâng cao công suất cho thiết bị. Trong bài báo này, một trong những giải pháp nâng cao mật độ năng lượng máy phát cũng như công suất thiết bị đã được nghiên cứu và phát triển. Để nâng cao mật độ năng lượng, các thiết kế dãy nam châm Halback đã được áp dụng. Mô hình mô phỏng và tính toán tối ưu cho các dãy nam châm đã được thực hiện để đảm bảo tăng sức mạnh của từ trường trong không gian của các cuộn dây. Mô hình máy phát tương ứng cũng đã được xây dựng và phát triển. các tính toán và tối ưu các thông số thiết kế cho việc tăng công suất máy phát cũng đã được thực hiện. Kết quả cho thấy công suất của thiết bị đã được nâng lên rõ rệt (hơn 10%) khi áp dụng thiết kế dãy Halback thay cho dãy nam châm thông thường trước đây.Huy Diep DoThe Ba Dangbadt@vnu.edu.vnVan Duc Nguyen2019-12-24T04:49:40Z2019-12-24T04:50:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3892This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38922019-12-24T04:49:40ZTính toán thiết kế phao tín hiệu đường thủy dùng năng lượng sóngCác thiết bị trên sông biển hoạt động cần nguồn điện, nhưng điều kiện cung cấp thường khó khan. Hơn nữa nhu cầu khai thác sử dụng năng lượng tái tạo đang là xu hướng tất yếu. Với đặc trưng hoạt động liên tục trên sông biển, nhưng lại cần nguồn điện liên tục, các phao tín hiệu cần nguồn cung cấp điện ổn định, chủ động. Báo cáo trình bày kết quả xây dựng thiết kế cấu tạo, mô hình hóa hoạt động và mô hình mô phỏng để tính toán hoạt động của phao báo hiệu dùng năng lượng sóng và mặt trời. Các tính toán mô phỏng đã được thực hiện để kiểm tra mô hình và hoạt động của thiết bị. Sau đó chương trình đã được sử đụng để tính toán xác định các thông số cấu tạo phục vụ công tác thiết kế. Các thiết bị chuyển đổi năng lượng sóng và mặt trời được thiết kế để cung cấp đủ nguồn điện nạp vào acquy. Mạch nạp và acquy được tính toán đảm bao nguồn điện ổn định 12V, phù hợp cung cấp cho các phụ kiện chức năng báo hiệu như đang sử dụng trên các phao báo hiệu hiện nay ở Việt Nam. Các thông số sẽ được sử dụng để thiết kế chế tạo thử nghiệm thiết bị hoạt động thực tế trong nghiên cứu tiếp theoThe Ba Dangbadt@vnu.edu.vnHai Yen PhamHuy Diep DoVan Duc Nguyen2019-12-24T04:48:37Z2019-12-24T04:49:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3891This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38912019-12-24T04:48:37ZNghiên cứu ứng dụng ảnh viễn thám xác định nồng độ chất rắn lơ lửng tại vùng cửa sông ven biển Đà Nẵng S¤NG VEN BIÓN §µ N½NGKết quả nghiên cứu sử dụng ảnh viễn thám xác định hàm lượng chất rắn lơ lửng (TSS) tại vùng cửa sông Hàn-Đà Nẵng cho thấy có sự phù hợp giữa điều kiện thực tế và số liệu tính toán cả về phân bố và nồng độ. Như vậy, sử dụng dữ liệu ảnh viễn thám có độ tin cậy là phương pháp hữu hiệu trong giám sát nồng độ TSS tại khu vực nghiên cứu, phục vụ quản lý môi trường trong phát triển kinh tế biển đảo.The Ba Dangbadt@vnu.edu.vnThi Huong LeThi Minh Hanh PhamThi Hong Van LeCong Dien Duong2019-12-24T04:48:22Z2019-12-24T04:48:22Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3890This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38902019-12-24T04:48:22ZThiết bị chuyển đổi năng lượng sóng biển sâuYêu cầu bảo hộ
1. Thiết bị chuyển đổi năng lượng sóng biển bao gồm:
phao thứ nhất (1) gồm có phần phao chính (101) có dạng hình trụ có bán kính đủ lớn để hấp thụ năng lượng sóng,
phao thứ hai (2) có dạng hình trụ có phần vỏ kéo dài (201) kéo dài lên phía trên bao quanh thanh nối (102) liên kết phao thứ nhất (1) và cuộn dây máy phát (105), và phần vỏ chứa máy phát (202) ở phía dưới để lắp vỏ máy phát tịnh tiến có gắn dãy nam châm máy phát (204),
phần vỏ kéo dài (201) có đường kính nhỏ để ít chịu tác động của sóng và có chiều dài đủ lớn để phần vỏ chứa máy phát (202) nằm xa khỏi vùng tập trung năng lượng sóng trên bề mặt sao cho phao thứ nhất (1) và phao thứ (2) chuyển động tương đối với nhau dưới tác động của sóng, khác biệt ở chỗ:
phần phao chính (101) của phao thứ nhất (1) được nối cứng với lồng gia tốc (103), lồng gia tốc (103) này có dạng ống hình trụ, mở hai đầu, có lắp ray trượt đĩa gia tốc (104) dọc thân lồng để định hướng trượt cho đĩa gia tốc (203) có khay trượt được gắn với phao thứ (2),
trong đó đĩa gia tốc (203) được bố trí trong lồng gia tốc (103), và kích thước lồng gia tốc (103) và đĩa gia tốc (203) được tính toán tối ưu hóa để thay đổi khối lượng nước kèm trong chuyển động của phao thứ hai (2) làm cho phao thứ hai (2) có dao động cơ bản gần ngược với phao thứ nhất (1) làm tăng chuyển động tương đối của phao thứ nhất (1) và phao thứ hai (2).
2. Thiết bị theo điểm 1, trong đó thiết bị này được lắp đặt tại các vùng biển sâu và được giữ bằng neo mềm.
3. Thiết bị theo điểm 1 hoặc 2, trong đó phần vỏ kéo dài (201) có chiều dài lớn hơn khoảng 10m để phần vỏ chứa máy phát (202) thoát khỏi vùng tập trung năng lượng sóng trên bề mặt.
4. Thiết bị theo điểm bất kỳ trong số các điểm từ 1 đến 3, trong đó phao thứ thứ nhất (1) có hai đầu được thết kế để dễ ổn định trên mặt sóng và hấp thụ tốt năng lượng sóng, lỗ trụ được tạo ra ở tâm phao thứ nhất (1) để phần vỏ kéo dài (201) của phao thứ hai (2) xuyên qua được và vượt khỏi mặt sóng sao cho phao thứ hai (2) có thể chuyển động tự do dọc theo lỗ trụ này.
5. Thiết bị theo điểm bất kỳ trong số các điểm từ 1 đến 4, trong đó phao thứ hai (2) có cấu tạo kín ở đầu phía dưới và hở đầu phía trên.
6. Thiết bị theo điểm bất kỳ trong số các điểm từ 1 đến 5, trong đó phao thứ nhất (1) được làm từ xốp hoặc nhựa composit.The Ba Dangbadt@vnu.edu.vn2019-12-24T04:47:20Z2019-12-26T11:00:46Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3881This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38812019-12-24T04:47:20ZStudy of Vibration of Dual-Buoy on the Linear
Electrical Generator for Wave Energy ConverterToday, Ocean wave energy is a renewable energy source with a large potential to contribute to the world’s electricity
production. This report presents the results on the modeling and optimization the systems of two buoys for wave energy converter. The
first is a floater. The second is a semi-submerged body. The energy is converted from the relative motion between the two buoys by the
linear generator. For simulation in three dimensions, the system of equations (6 modes of motions) has been obtained. The governing
equations are solved by ANSYS AQWA software and Matlab tools. In this report, Response Amplitude Operators (RAOs) are analysed.
Based on the RAOs results, we will determine the wave frequency domain for the maximum energy. The obtained results can be used for
the simulation, calculation and geometry optimization of the more realistic system in wave energy convertionHoang Quan Nguyenquannh@vnu.edu.vnThanh Tung Trantranthanhtung@vnu.edu.vn2019-12-24T04:46:13Z2019-12-24T04:46:13Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3879This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/38792019-12-24T04:46:13ZInfluence of different environement on the tribological behavior of
molybdenum disulfide MoS2Plastic materials are more and more important in our life. This article measure the thermal properties of some typical plastics materials by using the TMA Q400 machine. By comparision of their results and their chemical formulas will show their properties.
The tribological properties of molybdenite or molybdenum disulphide MoS2 depend on the relative humidity of gases surrounding the tribocontact. In high vacuum environments and in inert gases, the friction coefficient µ of molybdenum disulphide MoS2 is very low about µ=0,02 and in humid environments, the friction coefficient increases to µ = 0,18.
The objective of this study is to present the experimental results of the tribological properties of molybdenum disulfide MoS2 against steel XC48 in different gaseous environments (in high vacuum and ambient air). We calculate the potential energy between the gaseous molecules and the surface of adsorption or between these adsorbed gaseous molecules. We also try to estimate the interactions between the adsorbed gaseous molecules of the gap between the two consecutive layers of the crystal molybdenum disulfide MoS2. We discuss the effect of these interactions on the tribological characteristics of molybdenite MoS2.Hong Son Bui2019-12-12T11:02:56Z2019-12-12T11:03:42Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3764This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/37642019-12-12T11:02:56ZEmploying Extended Kalman Filter with Indoor Positioning System for Robot Localization ApplicationIPS (Indoor Positioning System) is used to localize the robot position in a narrow environment. However, IPS signal is not accurate in some cases, the IPS signal transmission will be obstructed by people the public museums, for example. The combination with other sensors will reduce the poor signal from IPS and noise in the environment with many obstacles. The Extended Kalman Filter (EKF) have been widely used for mobile robot localization system and gained certain results. In this paper, EKF is embedded to Central Processing Unit with Robot Operating System on “UET-FuSo”
robot to fuse IPS signal with encoder and IMU sensor for the determination of position and orientation robot. The obtained results show the effect of the proposed method when the robot localization is more stable and accurate than using only IPS signal. This localization will be applied for mapping and navigation of mobile robot in exhibition guidance robot.Huu Quoc Dong Trandongtran.robotics@gmail.comDuc Trinh Chutrinhcd@vnu.edu.vnThanh Tung Buitungbt@vnu.edu.vnThi Thanh Van Nguyenvannttuet@gmail.comHoang Anh Phananhph.robotic@gmail.comDinh Tuan Nguyenndinhtuan15@vnu.edu.vnDuy Nam Buiduynam.robotics@gmail.com2019-11-29T05:21:39Z2021-12-13T03:54:27Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3625This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36252019-11-29T05:21:39ZNumerical Investigation of Thermodynamic Parameter in Cavitating Flow of Liquid HydrogenMasaki NakanoAnh Dinh Leanh.ld@vnu.edu.vnJunnosuke OkajimaYuka Iga2019-11-28T01:44:53Z2019-11-29T05:47:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3655This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36552019-11-28T01:44:53ZA Research on Sensorless Control of Brushless DC Motor using Inductance Variation TechniqueToday, brushless DC motors (BLDCM) have been used in many applications replacing to brushed DC motors. Compared to brushed DC motors, BLDCM offer improved reliability, longer life, smaller size, and lower weight. Besides, BLDCM have become more popular in applications where efficiency is a critical concern and, generally speaking, a BLDCM is considered to be a high-performance motor capable of providing large amounts of torque over a wide speed range.
In this paper, a research on sensorless control method which can drive a BLDCM smoothly from standstill to high speeds without position or speed sensors is carried out. Initial rotor position as well as speed of motor at a low speed range is estimated based on the inductance variation principle while at higher speed, the back EMF technique is applied. This sensorless control algorithm is modeled and simulated with MATLAB/SIMULINK software to verify the abilities of the method. The drive control scheme has been implemented on a single-chip controller (STM32F103) and experimental results reveal that the control procedure can work smoothly.Hai Ninh DangQuang Tan NguyenNgoc Linh Nguyennlnguyen@vnu.edu.vn2019-11-28T01:44:40Z2019-11-29T05:46:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3656This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36562019-11-28T01:44:40ZA Research on Conveyor Belt 3D Printer in Industrial ApplicationsA 3d printing technique is an additive manufacturing technique where 3D objects and parts are made by the addition of multiple layers of material.[1] It is a type of rapid prototyping. The layers are stacked up in a variety of ways depending on the technology being used. It can use a wide range of materials such as ABS, PLA, and composites as well. This technology allows the design of complex components, therefore, avoiding assembly requirements at no additional cost.
This paper presents research on 3D printer design with a conveyor belt, which can be applied in industrial applications. Firstly, a CAD model of a 3d printer has been created using SolidWorks. In this step, all the parts of the model are designed and then are assembled in the SolidWorks workbench to create the 3D printer assembly. Then, the electronics board which controls the entire printing process is studied and integrated into the mechanical structure. The electronics board compiles the STL file to a suitable form to carry out the printing process and is connected to the PC using a USB-to-serial converter. Finally, a portable 3D printer is built and tested with various types of models.Dinh Hiep DamHoai Nam LeDuy Toan BuiNgoc Linh Nguyennlnguyen@vnu.edu.vn2019-11-27T06:57:06Z2019-11-27T06:57:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3618This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/36182019-11-27T06:57:06ZLagrangian Vortex Particle Method for Complex Flow SimulationIn order to solve complicated simulation problem for complex deforming objects under complicated motions found in aerospace, aerodynamic, meteorology, biology engineering, this paper presents Lagrangian vortex method based on Brinkman penalization. The Brinkman penalization acts as an external force, which is implicitly enforced into Navier-Stokes equation in the velocity-vorticity form. The advantage of the method is the capability to remove the pressure factor which causes errors in other numerical methods due to the complexity of shape of the object. Furthermore, the method is able to model the complex geometry, complex motions as well as 3D deformation of the object. In particular, the Navier-stokes equation can be solved in a classical strategy: applying Bio-Savart law formula is to deal with the convection process; employing fast multipole method to accelerate the velocity computation. The convergence is verified in several simulation applications such as air flow over low aspect ratio wing, rotation wings, influent of wind gust on high-raised building, and fish swimming.Viet Dung Duongduongdv@vnu.edu.vnZuhal Lavi RizkiMuhammad Hari2019-10-01T03:01:48Z2019-10-01T03:01:48Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3566This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/35662019-10-01T03:01:48ZAutomated robotic monitoring and inspection of steel structures and bridgesHung Manh LaTran Hiep Dinhtranhiep.dinh@vnu.edu.vnNhan Huu PhamQuang Phuc HaAnh Quyen Pham2019-07-05T03:06:17Z2019-07-05T03:06:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3493This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34932019-07-05T03:06:17ZNumerical analysis of the vibration response of skew magneto-electro-elastic plates based on the higher-order shear deformation theoryThis work addresses the problem of the three-dimensional free vibration behavior of skew magneto-electro-elastic plates under the framework of a higher order shear deformation theory. To this end, the finite element method was adopted considering the Hamilton’s principle. The results obtained from the present finite element model are verified with the simulation results of COMSOL software. Further, a parametric study is carried out to evaluate the influence of boundary conditions, stacking sequence, aspect ratio, and the length-to-width ratio. A special emphasis has been given to the natural frequency characteristics of multiphase skew magneto-electro-elastic plates as well. The results from the present analyses allow concluding on the significant influence that the geometrical skewness has on the free vibration behavior of these plates.Vinyas M.Nischith G.Loja M.A.R.Ebrahimi F.Dinh Duc Nguyenducnd@vnu.edu.vn2019-07-05T03:05:29Z2019-07-05T03:05:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3492This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34922019-07-05T03:05:29ZEffects of porosity and thermomechanical loading on free vibration and nonlinear dynamic response of functionally graded sandwich shells with double curvatureThe fundamental frequencies and nonlinear dynamic responses of functionally graded sandwich shells with double curvature under the influence of thermomechanical loadings and porosities are investigated in this study. Two material models are considered. The continuity requirement of material properties throughout layers are fulfilled by newly introducing refined effects of two porosity types regarding the average of constituent properties weighted by the porosity volume fraction. The first-order shear deformation theory taking the out-of-plane shear deformation into account is employed to obtain the Lagrange equation of motions. The number of primary variables reduces from five to three after introducing the Airy stress function. The system of dynamic governing equations is obtained by utilizing the Bubnov–Galerkin procedure. The natural frequencies are analytically computed by solving eigenvalue problems, and the fundamental frequencies are acquired by further assumptions about the inertial force caused by the shell rotation variables. The nonlinear dynamic responses of the functionally graded spherical, cylindrical, and hyperbolic paraboloid shells under the influence of different geometry configurations, loading conditions, and porosity types and degrees are obtained by applying the fourth-order Runge–Kutta method. The numerical results are presented and verified with available studies in the literature. Although porosities are usually considered material defects weakening the structure performance, this study has proved clearly that porosities stiffen the shell structures to some extent.Minh Chien TrinhDinh Duc Nguyenducnd@vnu.edu.vnSeung-Eock Kim2019-07-05T01:54:10Z2019-07-05T01:54:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3491This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34912019-07-05T01:54:10ZFree vibration and nonlinear dynamic response of imperfect nanocomposite FG-CNTRC double curved shallow shells in thermal environmentAnalytical solutions for the nonlinear vibration of imperfect functionally graded nanocomposite (FG-CNTRC) double curved shallow shells on elastic foundations subjected to mechanical load in thermal environments are introduced in this paper. The double curved shallow shells are reinforced by single-walled carbon nanotubes (SWCNTs) which are assumed to be graded through the thickness direction according to the different types of linear functions. Motion and compatibility equations are derived using Reddy's higher order shear deformation shell theory and taking into account the effects of initial geometrical imperfection and temperature – dependent properties. The deflection – time curve and the natural frequency are determined by using Galerkin method and fourth – order Runge – Kutta method. The effects geometrical parameters, elastic foundations, initial imperfection, temperature increment, mechanical loads and nanotube volume fraction on the nonlinear thermal vibration of the nanocomposite double curved shallow shells are discussed in numerical results. The accuracy of present approach and theoretical results is verified by some comparisons with the known data in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnHadavinia HomayounQuoc Quan Tranquantq1505@gmail.comDinh Khoa Nguyen2019-07-05T01:53:21Z2019-07-05T01:53:21Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3490This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34902019-07-05T01:53:21ZNonlinear thermal vibration of carbon nanotube polymer composite elliptical cylindrical shellsThis paper investigated the nonlinear
vibration and dynamic response of the carbon nanotube polymer composite elliptical cylindrical shells
on elastic foundations in thermal environment. The
material properties of the nanocomposite elliptical
cylindrical shells are assumed to depend on temperature and graded in the thickness direction according
to various linear functions. The shell is subjected to the
combination of the uniformly distributed transverse
load in harmonic form and the uniform temperature
rise. The motion and geometrical compatibility equations are derived based on the Reddy’s higher order
shear deformation shell theory. The natural frequencies and the deflection amplitude–time curves of the
shell are determined by using the Galerkin method and
fourth-order Runge–Kutta method. The numerical
results show not only the positive influences of carbonDinh Dat NgoQuoc Quan Tranquantq1505@gmail.comDinh Duc Nguyenducnd@vnu.edu.vn2019-07-05T01:51:19Z2019-07-05T01:51:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3488This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/34882019-07-05T01:51:19ZNonlinear vibration and dynamic buckling of eccentrically oblique stiffened FGM plates resting on elastic foundations in thermal environmentThis paper presents a semi-analytical approach to investigate the nonlinear dynamic response and vibration of eccentrically oblique stiffened functionally graded plate resting on elastic foundation. The Lekhnitskii's smeared stiffener technique is improved by using a transformation technique for oblique stiffeners. Governing equations are solved by classical shell theory, Galerkin method, stress function with temperature-dependent material effects. The results show the influences of geometrical parameters, material properties, imperfection, the elastic foundations, eccentrically oblique stiffeners, mechanical loads and temperature on the nonlinear dynamic response and nonlinear vibration of plates. The numerical results in this paper are compared with the results reported in other reports.Seung-Eock KimDinh Duc Nguyenducnd@vnu.edu.vnHoai Nam VuVan Sy Nguyen2019-01-07T02:22:05Z2019-01-07T02:22:05Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3374This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33742019-01-07T02:22:05ZNumerical Similation and Testing of a Two-Body Heaving Wave Energy ConverterVan Ngoc PhungThe Mich NguyenThe Ba Dangbadt@vnu.edu.vnDinh Do Chu2019-01-07T02:21:00Z2019-01-07T02:21:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3372This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33722019-01-07T02:21:00ZNumerical Analysis of a wave energy converter using linear generatorVan Ngoc PhungThe Mich NguyenThe Ba Dangbadt@vnu.edu.vnDinh Tuan Phan2019-01-02T03:25:02Z2019-01-02T03:25:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3371This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33712019-01-02T03:25:02ZMột Phương Pháp Mới Để Xác Định Phân Bố Thấm/Chứa Cho Mô Hình Mô Phỏng Mỏ Móng Nứt NẻTheo một cách làm thông dụng hiện nay, phân bố thấm/chứa của mô hình mô phỏng vỉa được xác định qua hai bước rời rạc: Trong bước thứ nhất, một quan hệ hồi quy mạng thần kinh nhân tạo (ANN) giữa thấm/chứa với các thuộc tính địa chấn được xây dựng và sử dụng để thu nhận phân bố thấm/chứa cho toàn mỏ; Trong bước tiếp theo, phân bố thấm/chứa này được hiệu chỉnh dựa trên dữ liệu khai thác (phục hồi lịch sử). Tuy nhiên, với đối tượng móng nứt nẻ, dữ liệu thấm/chứa mẫu dọc giếng (dùng để xây dựng quan hệ ANN) không phải là dữ liệu đo trực tiếp nên quan hệ ANN mang tính xấp xỉ cao và cần được hiệu chỉnh. Thêm vào đó, đặc tính địa cơ học được mong đợi là có quan hệ với mức độ nứt nẻ của mỏ móng nứt nẻ, vì vậy, nên được bổ xung trong phân tích quan hệ ANN với thấm chứa.
Với các nhận xét nói trên, chúng tôi đã phát triển một phương pháp mới để xác định phân bố thấm / rỗng cho mỏ móng nứt nẻ. Trong phương pháp này, quan hệ ANN giữa độ thấm/rỗng với các thuộc tính địa chấn và thông số địa cơ học được xây dựng và sau đó được hiệu chỉnh dựa trên số liệu khai thác. Hiệu chỉnh quan hệ ANN được thực hiện bằng cách sử dụng thuật toán tối ưu để hiệu chỉnh các hệ số truyền trong mạng ANN nhằm giảm thiểu sai khác giữa đo đạc và tính toán.Phương pháp mới này đã được áp dụng thử nghiệm để xác định phân bố thấm cho mô hình mô phỏng khai thác móng Bạch Hổ. Kết quả thử nghiệm đã cho thấy những ưu điểm và khả năng áp dụng của phương pháp.The Duc NguyenNgoc Trung PhanThe Ba Dangbadt@vnu.edu.vn2019-01-02T03:23:59Z2019-01-02T03:23:59Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3369This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33692019-01-02T03:23:59ZThe status and distribution of PCBs along the coast
of VietnamAbstract Polychlorinated biphenyls (PCBs), well-
known as an important scientiﬁc achievement, are now
considered as one of the most persistent organic
pollutants (POPs) that need to be strictly controlled
and forbidden worldwide (the Stockholm convention
on POPs). Vietnam is one of the countries that
encounters with serious issues from PCB contamina-
tion. This study presented a comprehensive review on
the status and contamination of PCBs along the coast
of Vietnam. The contaminated PCBs data in the water,
sediment and biological samples from 18 provinces
along Vietnam coastline were collected from various
sources. A comparison in PCBs contamination
between Vietnam and other Asian countries was
included. The status on PCBs contamination in
Vietnam since participated as a party of the Stockholm
convention on POPs in 2002 was also assessed. The
results showed that Vietnam is facing serious PCBs
contamination problems as it evidences the spread and
accumulation of PCBs in the marine environment. The
implementation of the Stockholm convention on POPs
(PCBs in particular) has not yet demonstrated signif-
icant effect on the reduction in PCBs contamination in
the environment. This information on PCBs contam-
ination in Vietnam urges government to strengthen the
mechanism, policy and legislation, the management
capacity for PCBs as well as applying advanced and
modern technologies in reducing, disposing and
eliminating PCBs from the environment.Thi Minh Hanh PhamThanh Nghi DuongDinh Lan TranVan Quan NguyenThe Ba Dangbadt@vnu.edu.vnHung Viet Pham2019-01-02T03:22:08Z2019-01-02T03:22:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3368This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33682019-01-02T03:22:08ZKHẢO SÁT ẢNH HƯỞNG VẬN TỐC PHUN NHIÊN LIỆU TỚI TRƯỜNG NHIỆT ĐỘ TRONG LÒ NUNG GỐM SỬ DỤNG GASNgày nay, tại các làng nghề sản xuất gốm sứ ở nước ta chủ yếu sử dụng lò nung gốm sứ dạng nhiên liệu gas. Phương pháp thiết kế các lò nung này chủ yếu vẫn dựa trên tính toán thiết kế truyền thông, tức là tính toán dựa trên phương trình cân bằng nhiệt lượng, nhiệt trị của nhiên liệu, lượng nhiên liệu cần thiết cung cấp để lò đạt tới giá trị thiết kế. Các phương pháp trên không cho ta biết trước được phân bố trường nhiệt độ, áp suất, vận tốc dòng khí diễn ra trong lò. Từ những thực tế trên, bài báo cáo này có mục đích giới thiệu phương pháp mô phỏng số trường nhiệt độ lò nung gas bằng phần mềm mô phỏng số CFD, ANSYS Fluent. Các qui trình mô phỏng tính toán sô sẽ được giới thiệu cụ thể. Một vài kết quả mô phỏng ảnh hưởng của trường vận tốc tới trường phân bố nhiệt độ sẽ được trình bàyHoang Quan Nguyenquannh@vnu.edu.vnTien Dung Truong2019-01-02T03:19:58Z2019-01-02T03:19:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3367This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33672019-01-02T03:19:58ZInvestigate magnetic field of dual Halbach array in linear generator using for wave energy conversionLinear permanent magnet machines have wide applications in various areas. In the wave energy conversion, the use of linear generator has earlier been regarded as difficult and uneconomical. Many attempts have been spent to overcome difficulties [15-17] however, for real field application, there are still many problems. In this study, an attempt to improve the magnetic flux density in linear generator has been investigated. A dual Halbach array structure is investigated on parameters of line generator in wave energy converter to enhance flux density in air gap, thus to improve output performance of linear machine. Numerical result from finite element method is employed to simulate and observe the flux distribution in the machine. The result also shows that the double Halbach array has increased magnetic flux density compared to the schema used in linear generator of Direct driven wave energy conversion.Huy Diep Dodohuydiep@gmail.comThe Ba Dangbadt@vnu.edu.vnVan Duc Nguyen2018-12-17T04:16:44Z2018-12-17T04:16:44Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3320This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/33202018-12-17T04:16:44ZPhát hiện vi khuẩn bằng đĩa giấy lọc hấp phụ luciferase và luciferinSự có mặt của các loại vi khuẩn trong môi trường không khí, đất, và nước là một trong những nguyên nhân chính gây ra các bệnh về đường hô hấp và các bệnh ngoài da cho con người và các loại vật nuôi. Do đó, việc phát hiện sớm các vi khuẩn quanh môi trường sống là yếu tố then chốt để ngăn chặn mối nguy hại phát sinh từ vi khuẩn. Trong nghiên cứu này, chúng tôi thiết kế và xây dựng một giấy lọc nhỏ có đường kính khoảng 0.5 cm được hấp phụ thêm luciferin và enzym luciferase. Giấy lọc này có khả năng định lượng được lượng vi khuẩn trong mẫu thông qua việc định lượng hàm lượng ATP có trong vi khuẩn. Quy trình chế tạo giấy lọc hấp phụ luciferase và luciferin đã được tối ưu hóa. Giấy lọc hấp phụ luciferase và luciferin cho thấy khả năng giữ ổn định luciferase và luciferin trong 30 ngày ở điều kiện nhiệt độ phòng, và khả năng phát hiện nồng độ E. coli có thể lên tới 1.17x 103 CFU/mL. Phương pháp phát hiện vi khuẩn qua việc định lượng hàm lượng ATP bằng giấy lọc hấp phụ luciferase và luciferin có thể giảm thời gian phát hiện vi khuẩn xuống còn 5 phút. Phương pháp xác định hàm lượng vi khuẩn bằng giấy lọc hấp phụ enzym luciferase và cơ chất luciferin là một phương pháp mới, triển vọng cao trong việc phát triển các cảm biến hóa sinh có độ chính xác cao và cho kết quả nhanh.Thi Dung NguyenDung.nguyenthi.tunhien@gmail.com2018-12-14T07:58:46Z2018-12-14T07:58:46Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3257This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32572018-12-14T07:58:46ZExperimental Characterization of an Ionically Conductive Fluid Based High Flexibility Strain SensorIn this study, a high flexibility strain sensor based on ionic liquid, which is a mixture of aqueous sodium chloride and glycerin pump in siliconen tube, is developed. Gold-coated electrodes are inserted into both ends of the tube to make good contact with the liquid. When the silicone tube is affected by an external force, its geometry and electrical characteristics of the mixture inside the tube are changed, resulting in the change in the sensor resistance. The proposed sensor was fabricated and experimentally characterized. The 4-point resistance measurement based on alternating Howland current source was applied to the sensor for measuring the change in resistance of the sensor. A circuit board with PIC16F877A microcontroller is also developed for data
acquisition and result display. Experimental results show that the sensor is
highly flexible, i.e., can suffer from a stretch up to 50% with stable gauge factor
in the range of 2.1 to 2.47. With its simplexes and high-flexibility, the proposed
sensor has high potential to be applied to wearable and portable applicationsNhu Chi Trantrannhuchi@vnu.edu.vnThi Thuy Ha TranHoai An TranHoang Nguyen TaThi Hoai NguyenNgoc An NguyenDuc Trinh Chutrinhcd@vnu.edu.vnThanh Van DauThanh Tung Buitungbt@vnu.edu.vn2018-12-14T01:33:30Z2018-12-18T08:22:32Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3239This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32392018-12-14T01:33:30ZFinite Element Modeling and Experimental Studies of Stack-Type Piezoelectric Energy HarvesterIn this paper, closed-form coupled electromechanical one-dimensional (1-D) model and finite
element (FE) model for stack-type piezoelectric energy harvester (PEH) and delivery to a resistive
load available in the literature were proposed. We obtained the values of some parameters of 1-D
model and set the boundaries of its applicability based on the comparison of the resonance frequency
and output voltage between the FE model and 1-D model. The numerical modeling results of the
full-scale experiment with low-frequency pulse excitation of the stack-type PEH for the energy
storage device are described. PEH is a multilayer axisymmetric piezoceramic package. The
dependence between the output voltage and the current load rate under the harmonic and nonstationary
mechanical action of the PEH is studied. The experimental results-to-numerical
calculation correlation has shown their good coincidence, which allows using the analyzed
numerical models to optimize the PEH design at the given external action frequency and the active
resistance value of the external electric circuit. Besides, it found that the frequency dependence of
the output voltage of the stack-type PEH is of a complex nature depending both on the compressive
pulse loading level and the piezoelectric modulus value of the PEH sensitive element, and on the
electrical load resistance.
Keywords: Finite element (FE), piezoelectric energy harvester (PEH), 1-D model, approximate
effective mass, stack-type, resonant frequency.V. Duong LeManh Thang Phamthangpm@vnu.edu.vnV.A. ChebanenkoA.N. SolovyevVan Chuong Nguyen2018-12-13T02:51:55Z2018-12-13T02:51:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3229This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32292018-12-13T02:51:55ZAnalytical approach to study nonlinear dynamic response and free vibration of laminated FG-CNTRC plates based on Reddy’s third-order laminated plate theoryThis work presents the nonlinear dynamic response and free vibration of laminated functionally graded
carbon nanotubes reinforced composite (FG-CNTRC) plates resting on elastic foundations. The laminated
nanocomposite plates are reinforced by single-walled carbon nanotubes (SWCNTs) that are assumed to be
uniformly distributed (UD) or functionally graded (FG) distributed along the thickness direction. The laminated
nanocomposite plates are made of various amorphous polymer matrices: Poly(methyl methacrylate) (PMMA) and
poly{(m-phenylenevinylene)-co-[(2,5-dioctoxy-p-phenylene) vinylene]} (PmPV). The nonlinear equations are
solved by both Galerkin method and Runge-Kutta method based on Reddy’s third-order laminated plate theory.
Detailed studies for the influences of various types of distribution and volume fractions of carbon nanotubes
(CNTs), geometrical parameters, Winkler and Pasternak elastic foundations on the nonlinear dynamic response and
natural frequencies and the number of layers and lamination angle of laminated FG-CNTRC plates are examined.Dinh Khoa NguyenDinh Nguyen Phamnguyenpd@vnu.edu.vn2018-12-13T02:51:08Z2018-12-13T02:51:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3226This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32262018-12-13T02:51:08ZAn analytical study on nonlinear buckling and post-buckling of laminated FG-GPLRC cylindrical panels resting on elastic foundationsThe main purpose of this paper is to investigate the nonlinear buckling and post-buckling analysis of
laminated functionally graded graphene nanoplatelets reinforced composite (FG-GPLRC) cylindrical panels resting
on viscoelastic foundations in the thermal environment. The weight fraction of GPL nanofillers layer-wisely alters
across the thickness direction of panels. Using the rule of the mixture and the modified Halpin-Tsai model, material
properties of the laminated nanocomposite cylindrical panels are estimated. The basic equations are based on the
first-order shear deformation shell theory and solved by Galerkin method. Detailed results for the effect of the GPL
distribution pattern, weight fraction, and elastic foundation models on the buckling loads and load-deflection curves
of laminated FG-GPLRC cylindrical panels are studied.Dinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDinh Nguyen Phamnguyenpd@vnu.edu.vn2018-12-12T15:19:56Z2018-12-12T15:19:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3225This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32252018-12-12T15:19:56ZAnalysis of unsymmetric FGM sandwich beams based on a new third-order shear deformation theory in high-temperature environmentPlate, shell, and beam made by functionally graded materials are widely used and applied in a high-
temperature working environment so that studying the mechanical behaviors of these structures is useful for its
applications in real life. In this paper, we present new results of static bending in high temperature and thermal
buckling of sandwich FG beam based on new third-order shear deformation theory (TSDT) and finite element
formulations. In the case of static bending, we assume the sandwich beam placed in a high-temperature environment
for a long time, and so that temperature distribution is uniform across the beam thickness. In the case of thermal
buckling, we focus on temperature-dependent material properties solution (called the TD). Using this TSDT, the
analysis does not need any shear correction factors and has no shear-locking. The results show that not all FGMs
could process similar to mechanical behaviors and have the ability to perform at high temperature.Van Thom DoHoang Nam Nguyennamnh@hus.edu.vnVan Minh PhungTrung Thanh TranVan Chinh NguyenDinh Duc Nguyenducnd@vnu.edu.vn2018-12-12T15:19:07Z2018-12-12T15:19:07Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3224This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32242018-12-12T15:19:07ZStatic bending and vibration analysis of two-layer composite plate based on first shear deformation theory using finite element methodA two-layer partial composite plate is a structure with outstanding advantages which can be widely applied
in many fields of engineering such as construction, transportation, mechanical, etc. However, there is no work in the
part to investigate this type of structure. This paper based on the first-order shear deformation plate theory (FSDT)
and finite element method (FEM) to develop a new four-node plate element with nine degrees of freedom per node
for static bending and vibration analysis of two-layer composite plate. The numerical results are compared with
published data for some special cases. The effects of some parametric such as boundary condition, stiffness of shear
connectors, height-to-width ratio are also performed to investigate.Van Vinh Phamvinhpv@gmail.comHoang Nam Nguyennamnh@hus.edu.vnVan Thom DoMinh Khoa NguyenDinh Duc Nguyenducnd@vnu.edu.vn2018-12-12T15:18:12Z2018-12-12T15:18:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3223This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32232018-12-12T15:18:12ZAnalysis of linear elastic fracture mechanics for cracked functionally graded composites by enhanced local enriched consecutive-interpolation elementsThis paper reports the application of consecutive-interpolation procedure into four-node quadrilateral
elements for analysis of two-dimensional cracked solids made of functionally graded composites. Compared to
standard finite element method, the recently developed consecutive-interpolation has been shown to possess many
desirable features, such as higher accuracy and smooth nodal gradients it still satisfies the Kronecker-delta property
and keeps the total number of degrees of freedom unchanged. The discontinuity in displacement fields along the
crack faces and stress singularity around the crack tips are mathematically modeled using enrichment functions. The
Heaviside function is employed to describe displacement jump, while four branch functions being developed from
asymptotic stress fields are taken as basis functions to capture singularities. The interesting characteristic of
functionally graded composites is the spatial variation of material properties which are intentionally designed to be
served for particular purposes. Such variation has to be taken into account during the computation of Stress Intensity
Factors (SIFs). Performance of the proposed approach is demonstrated and verified through various numerical
examples, in which SIFs are compared with reference solutions derived from other methods available in the
literature.Dinh Du NguyenNgoc Minh NguyenQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vn2018-12-12T15:17:25Z2018-12-12T15:17:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3222This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32222018-12-12T15:17:25ZNonlinear vibration analyses of functionally graded moderate thick toroidal shell segment within Reddy’s third-order shear deformation shell theoryFunctionally graded material (FGM) is a modern composite material created from two components metal and
ceramic. The FGM is both highly heat-resistant like the ceramic and good resilience just like metal. Today, FGMs
have been used in several industries such as aviation, space, and nuclear power. The knowledge of the buckling,
post-buckling, and vibration of FGM structures plays an important role in the design of these structures. In this
study, the nonlinear vibration of functionally graded moderate thick toroidal shell segment surrounded by an elastic
foundation are investigated. Based on the Reddy’s third-order shear deformation shell theory with the geometrical
nonlinear in von Karman sense and Galerkin’s method, the governing equations are derived. The effects of
temperature, material, dimension geometry parameters and foundations on characteristics of nonlinear vibration as
natural frequencies, dynamic responses of shells are examined.Minh Vuong PhamDinh Duc Nguyenducnd@vnu.edu.vn2018-12-12T15:16:41Z2018-12-12T15:16:41Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3221This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32212018-12-12T15:16:41ZBuckling analysis of cracked stiffened FGM plates by finite element methodFunctionally graded materials (FGMs) plate has the properties vary continuously in the thickness direction,
which has the cracks may be appeared, and the plate stiff reduce, easier to buckling, so that the studying of buckling
behaviors of this structure is useful. In this paper, the static buckling behaviors of cracked stiffened FGM plates are
studied by finite element method and phase-field theory based on the first order shear deformation theory. The
accuracy of this work is proved by comparing the results with respect to other studies. The effects of some
parameters of plate and stiffeners on static buckling are researched.Van Thom DoHoang Nam Nguyennamnh@hus.edu.vnHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnMinh Khoa NguyenDinh Duc Nguyenducnd@vnu.edu.vn2018-12-12T15:15:27Z2018-12-12T15:15:27Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3220This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32202018-12-12T15:15:27ZNonlinear dynamic analysis and vibration of shear deformable piezoelectric-FGM truncated conical shell resting on elastic foundations inthermal environmentsThis study investigates the nonlinear dynamic analysis and vibration of shear deformable FGM truncated
conical shell with piezoelectric actuators, resting on Pasternak type elastic foundations in thermal environments by
the analytical approach. Material properties are graded in the thickness direction according to a simple power law
distribution in terms of the fractions of constituents. The governing equations are based on the first-order shear
deformation theory (FSDT) with a von Karman-Donnell-type of kinematic nonlinearity. The Hamilton’s principle is
used to derive the equations of motion of piezoelectric FGM truncated conical shells. Those equations are solved by the Galerkin method and Runge-Kutta method. In numerical results, the effects of applied actuator voltage, temperature, dimensional parameters, semi-vertex angle, material properties and foundations on the nonlinear dynamic response and vibration of the piezoelectric FGM truncated conical shells are discussed in details.Dinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan TranQuang Chan Do2018-12-12T15:12:23Z2018-12-12T15:12:23Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3218This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32182018-12-12T15:12:23ZFree vibration analysis of functionally graded shells using an edge-based smoothed finite element methodAn edge-based smoothed finite element method (ES-FEM) combined with the mixed interpolation of tensorial components technique (MITC) for triangular elements (ESMITC3) for vibration analyses of functionally graded shells is investigated in this work. In the formulation of the ES-MITC3, the stiffness matrices are obtained by using the strain smoothing technique over the smoothing domains that formed by two adjacent MITC3 triangular shell elements sharing an edge. This strain smoothing technique can improve significantly the accuracy and
convergence of the original MITC3. The material properties of functionally graded shells are assumed to vary through the thickness direction by a power rule distribution of volume fractions of the constituents. The numerical examples demonstrated that the present ES-MITC3 method is free of shear locking and achieves the high accuracy compared to the exact solutions and others existing elements in the literature.Tien Dat PhamNam Hoang Nguyenhoangnn@vnu.edu.vnQuoc Hoa PhamVan Thom DoDinh Duc Nguyenducnd@vnu.edu.vn2018-12-12T15:10:25Z2018-12-12T15:10:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3228This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/32282018-12-12T15:10:25ZInvestigation on nonlinear dynamic response and free vibration of FG-CNTs reinforced composite truncated conical shells in the thermal environmentThe nonlinear dynamic response and free vibration of functionally graded carbon nanotubes (FG-CNTs)
reinforced composite truncated conical shells resting on elastic foundations in the thermal environment subjected to
axial load are carried out. The truncated conical shells are reinforced by single-walled carbon nanotubes (SWCNTs)
that are assumed to be uniformly distributed (UD) or functionally graded (FG) distributed along the thickness
direction. The nonlinear equations are solved by both Galerkin method and Runge-Kutta method based on the
classical shell theory with the geometrical nonlinear in von Karman and using the form of two-component deflection
function to solve the system of nonlinear partial differential equations. The material properties of FG-CNT
reinforced composite shells are assumed to be temperature-dependent. Detailed studies for the influences of various
types of distribution and volume fractions of carbon nanotubes, geometrical parameters, Winkler and Pasternak
elastic foundations on the nonlinear dynamic response and free vibration of FG-CNTRC truncated conical shells are
examined.Thi Thuy Anh Vuanhvutt@vnu.edu.vnDinh Nguyen Phamnguyenpd@vnu.edu.vn2018-11-26T06:01:00Z2018-11-26T06:01:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3136This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/31362018-11-26T06:01:00ZVibration and nonlinear dynamic response of eccentrically stiffened functionally graded composite truncated conical shells surrounded by an elastic medium in thermal environmentsA semi-analytical approach eccentrically stiffened functionally graded (ES-FGM) truncated conical shells surrounded by an elastic medium in thermal environments is presented. Based on the classical thin shell theory with the geometrical nonlinearity in von Karman Donnell sense, the smeared stiffeners technique and Galerkin method, this paper deals with vibration and nonlinear dynamic problem. The truncated conical shells are reinforced by ring stiffeners made of full metal or full ceramic depending on situation of stiffeners at the metal-rich or ceramic-rich side of the shell respectively. In addition, the study is not only assumed that the material properties depend on environment temperature variation, but also considered the thermal stresses in the stiffeners. Numerical results are given to evaluate effects of inhomogeneous, dimensional parameters, outside stiffeners, temperatures and elastic foundations to vibration and nonlinear dynamic response of structures.Quang Chan DoThi Thuy Anh Vuanhvutt@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vn2018-10-09T10:10:18Z2018-10-09T10:10:18Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3099This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30992018-10-09T10:10:18ZNonlinear stability of shallow spherical FG-CNTRC shell using FSDTDinh Duc Nguyenducnd@vnu.edu.vnThi Thuy Anh Vuanhvutt@vnu.edu.vnVan Kiet Dinh2018-10-09T10:09:45Z2018-10-09T10:09:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3096This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30962018-10-09T10:09:45ZFree vibration of cracked composite platesVan Thom DoHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vnTien Dat Pham2018-10-09T10:07:13Z2018-10-09T10:07:13Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3100This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/31002018-10-09T10:07:13ZBuckling analysis of FGM toroidal shell under torsional loadsDinh Duc Nguyenducnd@vnu.edu.vnMinh Vuong Pham2018-10-09T10:06:24Z2018-10-09T10:06:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3103This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/31032018-10-09T10:06:24ZA novel integration scheme for the consecutive-interpolation multilateral element to improve the stiffness matrixDinh Du NguyenDinh Duc Nguyenducnd@vnu.edu.vnQuoc Tinh Bui2018-10-09T10:00:44Z2018-10-09T10:00:44Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3102This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/31022018-10-09T10:00:44ZMechanical and thermal postbuckling of FG CNTRC thick circular cylindrical shells using higher-order shear deformation theoryDinh Duc Nguyenducnd@vnu.edu.vnThi Thiem Hoang2018-10-09T09:55:24Z2018-10-09T09:55:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3097This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30972018-10-09T09:55:24ZStatic bending analysis of variable-thickness FGM plates based on Mindlin theory and finite element methodTrung Thanh TranVan Thom DoTrac Luat DoanDinh Duc Nguyenducnd@vnu.edu.vn2018-10-09T09:52:28Z2018-10-09T09:52:28Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3077This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30772018-10-09T09:52:28ZNew approach to investigate nonlinear dynamic response of sandwich auxetic double curves shallow shells using TSDTNonlinear dynamic behavior of double curved shallow shells with negative Poisson’s ratios in auxetic honeycombs on elastic foundations subjected blast, mechanical and damping loads is investigated in the present article. This study considers double curved shallow shells with auxetic core which have three layers in which the top and the bottom outer skins are isotropic aluminum materials; the central layer has honeycomb structure using the same aluminum material. Based on the analytical solution, Reddy’s third order shear deformation theory (TSDT) with the geometrical nonlinear in von Karman and Airy stress functions method, Galerkin method and the fourth-order Runge-Kutta method, the resulting equations are solved to obtain expressions for nonlinear motion equations. The effects of geometrical parameters, material properties, elastic foundations, imperfections, blast loads, mechanical and damping loads on the nonlinear dynamic analysis of double curved shallow shells with negative Poisson’s ratios in auxetic honeycombs are studied.Hong Cong PhamDuy Khanh NguyenDinh Khoa NguyenDinh Duc Nguyenducnd@vnu.edu.vn2018-10-09T08:52:59Z2018-10-09T08:52:59Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3061This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30612018-10-09T08:52:59ZA static buckling investigation of multi-cracked FGM plate based phase-field method coupling the new TSDTDinh Duc Nguyenducnd@vnu.edu.vnHong Duc DoanVan Thom DoDuc Truong Trinh2018-10-09T08:49:41Z2018-10-09T08:49:41Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3059This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30592018-10-09T08:49:41ZVibration and nonlinear dynamic response of eccentrically stiffened functionally graded composite truncated conical shells in thermal environmentsQuang Chan DoThi Thuy Anh Vuanhvutt@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vn2018-08-27T01:35:30Z2018-08-27T01:35:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3047This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30472018-08-27T01:35:30ZStudy of the SPH Method for Simulation in LS-DYNAThe aim of this paper is to present the capabilities of Smoothed Particle Hydrodynamics (SPH) method in LS-DYNA. A new particle element has been added to LS-DYNA. It is based on Smoothed Particle Hydrodynamics theory. SPH is a meshless lagrangian numerical technique used to model the fluid equations of motion. SPH has proved to be useful in certain class of problems where large mesh distortions occur such as high velocity impact, crash simulations or compressible fluid dynamics. First, we introduce the basis principles of the SPH method. Then the coupling of this technique to LS-DYNA is presented and the input needed for such analysis is provided Two types of simulations have been comducted and show once again good capabilities of this new technology for both applicationsThanh Tung Trantranthanhtung@vnu.edu.vn2018-01-18T02:23:59Z2018-01-18T02:23:59Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2840This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28402018-01-18T02:23:59ZOn the buckling behavior of multi-cracked FGM platesDinh Duc Nguyenducnd@vnu.edu.vnDuc Trinh TruongVan Thom DoHong Duc Doandoan.hd.amsl.eng@vnu.edu.vn2018-01-18T02:22:53Z2018-01-18T02:22:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2838This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28382018-01-18T02:22:53ZPhase-field based simulation of treansverse cracking in laminatedHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnVan Thom DoDinh Khoa NguyenDinh Duc Nguyenducnd@vnu.edu.vn2018-01-18T02:22:19Z2018-01-18T02:22:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2837This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28372018-01-18T02:22:19ZThermal buckling of cracked Mindlin FGM plates based on neutral surface and phase-field methodVan Thom DoHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vn2018-01-18T02:21:45Z2018-01-18T02:21:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2836This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28362018-01-18T02:21:45ZNumerical validation for free vibration of cracked Mindlin plates using phase-field methodHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnVan Thom DoQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vn2018-01-18T02:21:03Z2018-01-18T02:21:03Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2835This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28352018-01-18T02:21:03ZNanocomposite materials for energy conversion and storageDinh Duc Nguyenducnd@vnu.edu.vn2018-01-18T02:20:04Z2018-01-18T02:20:04Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2839This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28392018-01-18T02:20:04ZNonlinear dynamic response of ES-FGM plate under blast loadHong Cong PhamDinh Duc Nguyenducnd@vnu.edu.vn2018-01-10T08:38:55Z2018-01-10T08:38:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2906This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/29062018-01-10T08:38:55ZThiết kế, chế tạo và thử nghiệm thiết bị chuyển đổi năng lượng sóng biển sâu công suất 40WBáo cáo trình bày kết quả tính toán, thiết kế chế tạo và thử nghiệm thiết bị chuyển đổi năng lượng sóng biển sâu dạng phao kép dùng máy phát tịnh tiến công suất 40W. Việc lựa chọn thiết bị cấu tạo kiểu phao kép kết hợp với sử dụng cơ cấu chuyển đổi trực tiếp dùng máy phát điện tịnh tiến đã khắc phục tốt được các rào cản kỹ thuật của những loại thiết bị đã được nghiên cứu trước đây. Thiết bị chuyển đổi năng lượng sóng biển đã chế tạo trong nghiên cứu này có tính cơ động, độ tin cậy cao; hoạt động không ảnh hưởng bởi thủy triều; dễ sản xuất, chế tạo và triển khai; không đòi hỏi quá trình xây dựng công trình biển phức tạp tốn kém; phạm vi ứng dụng và sử dụng rộng; dễ bảo hành, bảo trì. Kết quả kiểm tra thử nghiệm cho thấy thiết bị đáp ứng tốt yêu cầu và khả năng phát triển quy mô thực tếThe Ba Dangbadt@vnu.edu.vnVan Duc Nguyen2018-01-10T08:36:56Z2018-01-10T08:36:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2907This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/29072018-01-10T08:36:56ZMô phỏng số chuyển động sóng hai chiều bằng phần mềm ANSYS FLUENTTrong các hoạt động kinh tế xã hội biển, tác động của sóng luôn được quan tâm và tính toán. Các tính toán tác động của sóng trong kỹ thuật luôn được đề cập đến là xác định đặc trưng, từ đó tính toán tải sóng và dự đoán phản ứng của nó. Trong báo cáo này, kết quả mô phỏng tính toán chuyển động của sóng biển được trình bày. Công cụ mô phỏng là phần mềm thương mại ANSYS FLUENT. Mô hình dòng chảy hai pha chất lỏng nhớt, không nén được được sử dụng. Phương pháp tỷ phần chất lỏng biểu diễn sự tồn tại của các pha. Mô hình số hai chiều cho chuyển động sóng biến đã được xây dựng. Các điều kiện biên khác nhau được xác định và sử sử dụng đề mô tả biên phía bờ biển cho các trường hợp khác nhau. Sóng được tạo ra do chuyển động của một biên cứng như trong bể tạo sóng. Các biên còn lại tương ứng là biên tường trượt và không trượt. Kết quả mô phỏng tốt các trường sóng tuyến tính và phù hợp tốt với các lời giải giải tích. Bài toán sẽ được phát triển để mô phỏng tác động sóng lên phao làm cơ sở tính toán thiết kế phao chuyển đổi năng lượng sóng cũng như tác động của sóng lên các dạng bờ khác nhau làm cơ sở cho việc xây dựng, quy hoạch và bảo vệ bờ biển.The Ba Dangbadt@vnu.edu.vn2017-12-25T04:17:52Z2017-12-25T04:17:52Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2842This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28422017-12-25T04:17:52ZNew approach to investigate nonlinear dynamic response of
sandwich auxetic double curves shallow shells using TSDTNonlinear dynamic behavior of double curved shallow shells with negative Poisson’s ratios in auxetic honeycombs on elastic foundations subjected blast, mechanical and damping loads is investigated in the present article. This study considers double curved shallow shells with auxetic core which have three layers in which the
top and the bottom outer skins are isotropic aluminum materials; the central layer has honeycomb structure
using the same aluminum material. Based on the analytical solution, Reddy’s third order shear deformation
theory (TSDT) with the geometrical nonlinear in von Karman and Airy stress functions method, Galerkin method
and the fourth-order Runge-Kutta method, the resulting equations are solved to obtain expressions for nonlinear
motion equations. The effects of geometrical parameters, material properties, elastic foundations, imperfections,
blast loads, mechanical and damping loads on the nonlinear dynamic analysis of double curved shallow shells
with negative Poisson’s ratios in auxetic honeycombs are studied.Hong Cong PhamDuy Khanh NguyenDinh Khoa NguyenDinh Duc Nguyenducnd@vnu.edu.vn2017-12-25T04:01:08Z2017-12-25T04:01:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2833This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28332017-12-25T04:01:08ZNonlinear dynamic response and vibration of imperfect shear deformable functionally graded plates subjected to blast and thermal loadsBased on Reddy's higher-order shear deformation plate theory, this article presents an analysis of the nonlinear dynamic response and vibration of imperfect functionally graded material (FGM) thick plates subjected to blast and thermal loads resting on elastic foundations. The material properties are assumed to be temperature-dependent and graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. Numerical results for the dynamic response and vibration of the FGM plates with two cases of boundary conditions are obtained by the Galerkin method and fourth-order Runge–Kutta method. The results show the effects of geometrical parameters, material properties, imperfections, temperature increment, elastic foundations, and boundary conditions on the nonlinear dynamic response and vibration of FGM plates.Dinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoTran PhuongQuoc Quan Tran2017-12-25T04:00:17Z2017-12-25T04:00:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2832This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28322017-12-25T04:00:17ZNonlinear thermal stability of eccentrically stiffened FGM double curved shallow shellsThis article presents analytical solutions for the nonlinear static and dynamic stability of imperfect eccentrically stiffened functionally graded material (FGM) higher order shear deformable double curved shallow shell on elastic foundations in thermal environments. It is assumed that the shell’s properties depend on temperature and change according to the power functions of the shell thickness. The shell is reinforced by the eccentrically longitudinal and transversal stiffeners made of full metal. Equilibrium, motion, and compatibility equations are derived using Reddy’s higher order shear deformation shell theory and taking into account the effects of initial geometric imperfection and the thermal stress in both the shells and stiffeners. The Galerkin method is applied to determine load–deflection and deflection–time curves. For the dynamical response, motion equations are numerically solved using Runge–Kutta method. The nonlinear dynamic critical buckling loads are found according to the criterion suggested by Budiansky–Roth. The influences of inhomogeneous parameters, dimensional parameters, stiffeners, elastic foundations, initial imperfection, and temperature increment on the nonlinear static and dynamic stability of thick FGM double curved shallow shells are discussed in detail. Results for various problems are included to verify the accuracy and eﬃciency of the approach.Quoc Quan TranDinh Duc Nguyenducnd@vnu.edu.vn2017-12-25T03:50:06Z2017-12-25T03:50:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2829This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28292017-12-25T03:50:06ZThermal and mechanical stability of functionally graded carbon nanotubes
(FG CNT)-reinforced composite truncated conical shells surrounded by the
elastic foundationsThe thermal and mechanical stability of a functionally graded composite truncated conical shell reinforced by
carbon nanotube fibers and surrounded by the elastic foundations are studied in this paper. Distribution of
reinforcements across the shell thickness is assumed to be uniform or functionally graded. The equilibrium and
linearized stability equations for the shells are derived based on the classical shell theory. Using Galerkin
method, the closed – form expression for determining the linear thermal and mechanical buckling load is
obtained. The paper also analyzed and discussed the effects of semi-vertex angle, shell length, volume fraction of
fibers, distribution pattern of fibers, temperature, elastic foundations on the linear thermal and mechanical
buckling loads of the functionally graded carbon nanotube fibers-reinforced composite (FG CNTRC) truncated
conical shell in thermal environment.Dinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDuc Tuan NgoTran PhuongVan Thanh Nguyen2017-12-25T03:49:20Z2017-12-25T03:49:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2828This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28282017-12-25T03:49:20ZConstitutive modeling of cyclic plasticity deformation and low–high-cycle fatigue of stainless steel 304 in uniaxial stress stateFor constructing a theory that adequately describes the effects of cycling loading, we initially analyze an experimental plastic hysteresis loop of the stainless steel SS304 and allocate on it three backstress types responsible for yield surface center displacement. Evolutionary equations per each backstresses type are formulated based on the equation of plasticity flow theory at combined (isotropic-kinematic) hardening. Material functions (parameters) closing the theory are defined, and basic experiment and identification methods of material function are formulated. Comparison of design results and experiments testifies their reliable compatibility.Valentin S. BondarVladimir V. DansinLong D.VuDinh Duc Nguyenducnd@vnu.edu.vn2017-12-25T03:48:53Z2017-12-25T03:48:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2827This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28272017-12-25T03:48:53ZNonlinear buckling and postbuckling of imperfect piezoelectric S-FGM circular cylindrical shells with metal–ceramic–metal layers in thermal environment using Reddy's third-order shear deformation shell theoryBased on Reddy's third-order shear deformation shell theory, this paper studied the nonlinear buckling and postbuckling response of imperfect Sigmoid functionally graded circular cylindrical shells in a thermal environment with an outer surface-bonded piezoelectric actuator. Material properties are temperature dependent and graded in the thickness direction with two shell's outer surfaces rich of metal and ceramic in the middle (S-FGM). The shell is subjected to uniform external pressure, axial compressive, electrical loads and resting on elastic foundations. The obtained numerical results are validated by comparing with other results reported in the open literature.Dinh Khoa NguyenThi Thiem HoangDinh Duc Nguyenducnd@vnu.edu.vn2017-12-25T03:48:24Z2017-12-25T07:21:38Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2826This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28262017-12-25T03:48:24ZNonlinear thermo-mechanical response of eccentrically stiffened Sigmoid FGM circular cylindrical shells subjected to compressive and uniform radial loads using the Reddy's third-order shear deformation shell theoryBased on Reddy's third-order shear deformation shell theory, this paper presents an analytical approach to investigate the nonlinear thermo-mechanical response of imperfect Sigmoid FGM circular cylindrical shells surrounded on elastic foundations and reinforced by outside metal stiffeners. The eccentrically stiffened S-FGM shells are subjected to axial compressive load and uniform radial load in thermal environment. Using the stress function, Bubnov–Galerkin method, the paper proposes the formula for forces and moments taking into account the thermal stress in both the shells and stiffeners. The obtained results are validated by comparing with other results reported in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnDinh Khoa NguyenThi Thiem Hoang2017-12-25T03:48:08Z2017-12-25T03:48:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2825This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28252017-12-25T03:48:08ZThermomechanical buckling and post-buckling of cylindrical shell with functionally graded coatings and reinforced by stringersThe cylindrical shells reinforced by stringers have been widely used in modern engineering structures such as storage tanks, missile, submarine hull, oil-transmitting pipeline, etc. In this present article, the thermomechanical buckling and post-buckling behaviors of a cylindrical shell with functionally graded (FG) coatings are investigated by an analytical approach. The cylindrical shell is reinforced by outside stringers under torsional load in the thermal environment. The layers of FG coatings are assumed to be made by functionally graded materials (FGMS) combining of ceramic and metal phases and the core of the shell is made from homogeneous material. The classical shell theory based on the von-Karman assumptions is used to model the thin cylindrical shell. Using Galerkin's procedure and Airy stress function, the governing equations can be solved to obtain the closed-form solution for the critical buckling load and postbuckling load-deflection curves of simply supported shells. Moreover, many important parametric studies of stringers, temperature field, material volume fraction index, the thickness of metal layer, etc. are taken into investigation. According to numerical examples, it is revealed that the outside strings have considerably impact on thermomechanical buckling and postbuckling behaviors of the shells.Toan Thang PhamDinh Duc Nguyenducnd@vnu.edu.vnThoi Trung Nguyen2017-12-25T03:47:31Z2017-12-25T03:47:31Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2824This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28242017-12-25T03:47:31ZNonlinear dynamic response and vibration of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) shear deformable plates with temperature dependence material properties and surrounded on elastic foundationsBased on Reddy’s third-order shear deformation plate theory, the nonlinear dynamic response and vibration of imperfect functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates on elastic foundations subjected to dynamic loads and temperature are presented. The plates are reinforced by single-walled carbon nanotubes which vary according to the linear functions of the plate thickness. The plate’s effective material properties are assumed to depend on temperature and estimated through the rule of mixture. By applying the Airy stress function, Galerkin method and fourth-order Runge–Kutta method, nonlinear dynamic response and natural frequency for imperfect FG-CNTRC plates are determined. In numerical results, the influences of geometrical parameters, elastic foundations, initial imperfection, dynamic loads, temperature increment, and nanotube volume fraction on the nonlinear vibration of FG-CNTRC plates are investigated. The obtained results are validated by comparing with those of other authors.Van Thanh NguyenDinh Khoa NguyenDuc Tuan NgoPhuong TranDinh Duc Nguyenducnd@vnu.edu.vn2017-12-20T04:55:33Z2017-12-20T04:55:33Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2822This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28222017-12-20T04:55:33ZAnalysis of bi-directional functionally graded plates by FEM and a new third-order shear deformation plate theoryonly in one specified direction, but also different other directions. In particular, the bi-directional functionally
graded materials (2D-FGMs) introduced are expected to have more effective properties, consequently eliminating
commonly awkward problems such as local stress concentrations and delamination. In this paper,
buckling and bending behaviors of 2D-FGM plates, which are of great importance in the design and development
of engineering applications, are numerically analyzed by a finite element model. The plate kinematics are described
using a new third-order shear deformation plate theory (TSDT), without the need for special treatment of
shear-locking effect and shear correction factors. The present TSDT theory based on rigorous kinematic of displacements,
which is shown to be dominated over other preceding theories, is derived from an elasticity formulation,
rather by the hypothesis of displacements. The materials are assumed to be graded in two directions
and their effective properties are computed through the rule of mixture. The accuracy of the proposed approach
assessed on numerical results is confirmed by comparing the obtained results with respect to reference published
solutions. The effects of some numerical aspect ratios such as volume fraction, boundary conditions, thickness to
length ratio, etc. on static deflections and critical buckling are numerically studied. The investigation of results
confirms that such aforementioned aspect ratios have significant effects on the mechanical behaviors of plates.Van Thom DoDinh Kien NguyenDinh Duc Nguyenducnd@vnu.edu.vnHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh Bui2017-12-20T04:55:12Z2017-12-20T04:55:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2823This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28232017-12-20T04:55:12ZStatic response and free vibration of functionally graded carbon nanotube-reinforced composite rectangular plates resting on Winkler–Pasternak elastic foundationsIn the present article, static response and free vibration of functionally graded carbon nanotube
reinforced composite (FG-CNTRC) rectangular plate resting on Winkler–Pasternak elastic foundations
using an analytical approach are studied. The rectangular plates are reinforced by single-walled carbon
nanotubes (SWCNTs) which are assumed to be graded through the thickness direction with four types
of distributions. The mathematical model of the FG-CNTRC plate is developed based on the first-order
shear deformation plate theory (FSDT) and Hamilton principle. By using Navier solution, the governing
equations are solved to obtain the central deflection and the natural frequency parameters. Several
examples are verified to have higher accuracy than those from the previous method in the literature.
Also, the effects of different parameters on static response and natural frequency of FG-CNTRC plate are
highlighted by solving numerous examples. Finally, these new results may serve as benchmarks for future
investigations.Dinh Duc Nguyenducnd@vnu.edu.vnJaehong LeeThoi Trung NguyenToan Thang Pham2017-12-20T04:25:14Z2017-12-20T04:25:14Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2820This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28202017-12-20T04:25:14ZNew approach to study nonlinear dynamic response and vibration of sandwich composite cylindrical panels with auxetic honeycomb core layerThe main goal of this study is using analytical solution to investigate the nonlinear dynamic response and
vibration of sandwich auxetic composite cylindrical panels. The sandwich composite panels have three
layers in which the top and bottom outer skins are isotropic aluminum materials, the central auxetic
core layer – honeycomb structures with negative Poisson’s ratio using the same aluminum material. The
panels are resting on elastic foundations and subjected to mechanical, blast and damping loads. Based
on Reddy’s first order shear deformation theory (FSDT) with the geometrical nonlinear in von Karman
and using the Airy stress functions method, Galerkin method and fourth-order Runge–Kutta method,
the resulting equations are solved to obtain expressions for nonlinear motion equations. The effects
of geometrical parameters, material properties, elastic Winkler and Pasternak foundations, mechanical,
blast and damping loads on the nonlinear dynamic response and the natural frequencies of sandwich
composite cylindrical panels are studied.Dinh Duc Nguyenducnd@vnu.edu.vnSeung-Eock KimDuc Tuan NgoPhuong Tran2017-12-20T04:24:20Z2017-12-20T04:24:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2819This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28192017-12-20T04:24:20ZA rate-dependent hybrid phase field model for dynamic crack propagationSeveral models of variational phase field for fracture have been introduced and analyzed to different degrees of applications, and the rate-independent phase field approach has been shown to be a versatile one, but it is not able to accurately capture crack velocity and dissipated energy in dynamic crack propagation. In this paper, we introduce a novel rate-dependent regularized phase field approach to study dynamic fracture behaviors of polymethylmethacrylate materials, in which the rate coefficient is estimated through energy balance, i.e., dynamics release energy, cohesive energy and dissipated energy. The mode-I dynamics crack problem is considered, and its accuracy is validated with respect to experimental data [F. Zhou, Ph.D. dissertation (The University of Tokyo, Japan, 1996)] and other numerical methods, taking the same configuration, material property, crack location, and other relevant assumptions. The results shed light on the requirement and need for taking the rate-dependent coefficient in dynamic fracture analysis.Hong Duc DoanQuoc Tinh BuiVan Thom DoDinh Duc Nguyenducnd@vnu.edu.vn2017-12-20T03:03:16Z2017-12-20T03:03:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2816This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28162017-12-20T03:03:16ZLight absorption, luminescence, dynamic response and vibration of nanocomposite organic solar cellsDinh Duc Nguyenducnd@vnu.edu.vn2017-12-20T03:01:51Z2017-12-20T03:01:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2815This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28152017-12-20T03:01:51ZNanocomposite structure for organic photovoltaic devicesDinh Duc Nguyenducnd@vnu.edu.vn2017-12-20T03:01:14Z2017-12-20T03:01:14Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2814This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28142017-12-20T03:01:14ZNonlinear thermal dynamic analysis of eccentrically stiffened FGM structures usinh HSDTDinh Duc Nguyenducnd@vnu.edu.vn2017-12-20T02:58:34Z2017-12-20T02:58:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2818This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28182017-12-20T02:58:34ZDynamic response and vibration of composite double curved shallow shells with negative Poisson’s ratio in auxetic honeycombs core layer on elastic foundations subjected to blast and damping loadsThe purpose of the present study is to investigate dynamic response and vibration of composite double curved
shallow shells with negative Poisson’s ratios in auxetic honeycombs core layer on elastic foundations subjected
to blast and damping loads using analytical solution. This study considers composite double curved shallow
shells with auxetic core which have three layers in which the top and bottom outer skins are isotropic aluminum
materials; the central layer has honeycomb structure using the same aluminum material. Based on the first order
shear deformation theory (FSDT) with the geometrical nonlinear in von Karman and using Airy stress functions
method, Galerkin method and the fourth-order Runge–Kutta method, the resulting equations are solved to obtain
expressions for nonlinear motion equations. The effects of geometrical parameters, material properties, elastic
foundations Winkler and Pasternak, the nonlinear dynamic analysis and vibration of double curved shallow shells
with negative Poisson’s ratios in auxetic honeycombs core layer are studiedDinh Duc Nguyenducnd@vnu.edu.vnSeung-Eock KimHong Cong PhamTuan Anh NguyenDinh Khoa Nguyen2017-12-20T02:57:12Z2017-12-20T02:57:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2812This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28122017-12-20T02:57:12ZNew approach to investigate nonlinear dynamic response and vibration of imperfect functionally graded carbon nanotube reinforced composite double curved shallow shells subjected to blast load and temperatureThis paper presents a new approach – using analytical solution to investigate nonlinear dynamic response and vibration of imperfect functionally graded carbon nanotube reinforced composite (FG-CNTRC) double curved shallow shells. The double curved shallow shells are reinforced by single-walled carbon nanotubes (SWCNTs) which vary according to the linear functions of the shell thickness. The shells are resting on elastic foundations and subjected to blast load and temperature. The shell's effective material properties are assumed to depend on temperature and estimated through the rule of mixture. By applying higher order shear theory, Galerkin method and fourth-order Runge–Kutta method and the Airy stress function, nonlinear dynamic response and natural frequency for thick imperfect FG-CNTRC double curved shallow shells are determined. In numerical results, the influences of geometrical parameters, elastic foundations, initial imperfection, temperature increment and nanotube volume fraction on the nonlinear vibration of the FG-CNTRC double curved shallow shells are investigated. The proposed results are validated by comparing with those of other authors.Dinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan TranDinh Khoa Nguyen2017-12-20T02:56:00Z2017-12-20T02:56:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2810This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28102017-12-20T02:56:00ZThe effects of strength models in numerical study of metal plate destruction by contact xeplosive chargeTuan Anh TruongVan Thom DoTien Dat PhamDinh Duc Nguyenducnd@vnu.edu.vn2017-12-20T02:55:17Z2017-12-20T02:55:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2811This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28112017-12-20T02:55:17ZDYNAMIC ANALYSIS OF IMPERFECT FGM CIRCULAR CYLINDRICAL SHELLS REINFORCED BY FGM STIFFENER SYSTEM USING THIRD ORDER SHEAR DEFORMATION THEORY IN TERM OF DISPLACEMENT COMPONENTSTHIS PAPER PRESENTS DYNAMIC ANALYSIS OF AN ECCENTRICALLY STIFFENED IMPERFECT CIRCULAR CYLINDRICAL SHELLS MADE OF FUNCTIONALLY GRADED MATERIALS, SUBJECTED TO AXIAL COMPRESSIVE LOAD AND FILLED INSIDE BY ELASTIC FOUNDATIONS IN THERMAL ENVIRONMENTS BY ANALYTICAL METHOD. SHELLS ARE REINFORCED BY FGM STRINGERS AND RINGS TAKING INTO ACCOUNT THERMAL ELEMENTS. THE STABILITY EQUATIONS IN TERMS OF DISPLACEMENT COMPONENTS FOR STIFFENED SHELLS ARE DERIVED BY USING THE THIRD-ORDER SHEAR DEFORMATION THEORY AND SMEARED STIFFENERS TECHNIQUE. THE CLOSED-FORM EXPRESSIONS FOR DETERMINING THE NATURAL FREQUENCY, NONLINEAR FREQUENCY-AMPLITUDE CURVE AND NONLINEAR DYNAMIC RESPONSE ARE OBTAINED BY USING GALERKIN MET-HOD AND FOURTH-ORDER RUNGE-KUTTA METHOD. THE EFFECTS OF STIFFENERS, FOUNDATIONS, IMPERFECTION, MATERIAL AND DIMENSIONAL PARA-METERS PRE-EXISTENT AXIAL COMPRESSIVE AND THERMAL LOAD ON DYNAMIC RESPONSES OF SHELLS ARE CONSIDERED.Van Dung DaoDinh Duc Nguyenducnd@vnu.edu.vnThi Thiem Hoang2017-12-20T02:54:24Z2017-12-20T02:54:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2809This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28092017-12-20T02:54:24ZThermal buckling analysis of FGM sandwich truncated conical shells reinforced by FGM stiffeners resting on elastic foundations using FSDTThis work presents an analytical approach to investigate the mechanical and thermal buckling of functionally graded materials sandwich truncated conical shells resting on Pasternak elastic foundations, subjected to thermal load and axial compressive load. Shells are reinforced by closely spaced stringers and rings, in which the material properties of shells and stieners are graded in the
thickness direction following a general sigmoid law distribution and a general power law distribution. Four models of coated shell-stiener arrangements are investigated. The change of spacing between stringers in the meridional direction also is taken into account. Two cases on uniform temperature rise and linear temperature distribution through the thickness of shell are considered. Using the rst-order shear deformation theory, Lekhnitskii smeared stiener technique and the adjacent equilibrium criterion, the linearization stability
equations have been established. Approximate solution satises simply supported boundary conditions and Galerkin method is applied to obtain closed-form expression for determining the critical compression buckling
load and thermal buckling load in cases uniform temperature rise and linear temperature distribution across the shell thickness. The eects of temperature,
foundation, core layer, coating layer, stieners,
material properties, dimensional parameters and semi-vertex angle on buckling behaviors of shell are shown.Dinh Duc Nguyenducnd@vnu.edu.vnSeung-Eock KimQuang Chan Do2017-12-20T02:51:47Z2017-12-20T02:51:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2808This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28082017-12-20T02:51:47ZPhase-field thermal buckling analysis for cracked functionally graded composite plates considering neutral surfaceIn this paper, the variational phase field model is adopted to analyze thermal buckling behavior of cracked
functionally graded material (FGM) plates. Unlike existing works, the difference between neutral surface and
mid-surface of FGM plates is taken into account in the present study. The kinematics of plate is based on first
order shear deformation theory, while the crack is simulated by variational phase-field theory. The critical
buckling temperature rises of cracked FGM plate is calculated, and the obtained results are then compared with
those derived from extended isogeometric analysis by the authors and other numerical methods. We analyze the
thermal buckling of cracked FGM plates for both cases: (a) the mid-surface coincides neutral surface, and (b)
they are different between each other, and then showing their influence. We also investigate the effects of
boundary condition and material properties on thermal buckling of cracked FGM plate. Through these results, it
reveals the necessity to consider the difference between neutral surface and mid-surface in thermal buckling
analysis.Van Thom DoHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vnQuoc Tinh Bui2017-12-20T02:51:01Z2017-12-20T02:51:01Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2813This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28132017-12-20T02:51:01ZNonlinear dynamic analysis and vibration of eccentrically stiffened S-FGM elliptical cylindrical shells surrounded on elastic foundations in thermal
environmentsElliptical cylindrical shell is one of shells with special shape. Up to date, there is no publication on vibration and dynamic of functionally graded elliptical cylindrical shells. Therefore, the purpose of the present study is to
investigate the nonlinear dynamic response and vibration of imperfect eccentrically stiffness functionally graded
elliptical cylindrical shells on elastic foundations using both the classical shell theory (CST) and Airy stress
functions method with motion equations using Volmir's assumption. The material properties are assumed to be
temperature - dependent and graded in the thickness direction according to a Sigmoid power law distribution (S
FGM). The S-FGM elliptical cylindrical shell with metal-ceramic-metal layers are reinforced by outside metal
stiffeners. Both the S-FGM elliptical shell and metal stiffeners are assumed to be in thermal environment and
both of them are deformed under temperature simultaneously. Two cases of thermal loading (uniform
temperature rise and temperature variation through thickness) are considered. The nonlinear motion equations
are solved by Galerkin method and Runge-Kutta method (nonlinear dynamic response, natural frequencies). The
effects of geometrical parameters, material properties, elastic foundations Winkler and Pasternak, the nonlinear
dynamic analysis and nonlinear vibration of the elliptical cylindrical shells are studied. The some obtained
results are validated by comparing with those in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnDinh Nguyen PhamDinh Khoa Nguyen2017-12-20T02:47:51Z2017-12-20T02:47:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2805This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28052017-12-20T02:47:51ZThe dynamic response and vibration of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) truncated conical shells resting on elastic foundationBased on the classical shell theory, the linear dynamic response of functionally graded
carbon nanotube-reinforced composite (FG-CNTRC) truncated conical shells resting on elastic
foundations subjected to dynamic loads is presented. The truncated conical shells are reinforced by
single-walled carbon nanotubes (SWCNTs) that vary according to the linear functions of the shell
thickness. The motion equations are solved by the Galerkin method and the fourth-order Runge–Kutta
method. In numerical results, the influences of geometrical parameters, elastic foundations, natural
frequency parameters, and nanotube volume fraction of FG-CNTRC truncated conical shells are
investigated. The proposed results are validated by comparing them with those of other authors.Dinh Duc Nguyenducnd@vnu.edu.vnDinh Nguyen Phamnguyenpd_58@vnu.edu.vn2017-12-20T02:45:16Z2017-12-20T02:45:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2804This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/28042017-12-20T02:45:16ZNonlinear dynamic response and vibration of nanocomposite multilayer organic solar cellIn the recent years, organic solar cell (OSC) has attracted much interest of the research community due to its great promise as renewable sources. This paper presents the first analytical approach to investigate the nonlinear dynamic response and vibration of imperfect rectangular nanocompsite multilayer organic solar cell subjected to mechanical loads using the classical plate theory. Nanocompsite organic solar cell consists of five layers of Al, P3HT:PCBM, PEDOT:PSS, IOT and glass. Motion and compatibility equations are derived using the classical plate theory and taking into account the effects of initial geometrical imperfection and geometrical nonlinearity in
Von Karman – Donnell sense. The Galerkin method and fourth – order Runge – Kutta method are used to give
explicit expressions of natural frequencies, nonlinear frequency – amplitude relation and nonlinear dynamic
responses of nanocompsite organic solar cell. The numerical results show the influences of geometrical parameters,
the thickness of layers, imperfections, and mechanical loads on the nonlinear dynamic response and
nonlinear vibration of nanocompsite organic solar cell.Dinh Duc Nguyenducnd@vnu.edu.vnSeung-Eock KimQuoc Quan TranDinh Long Dangddlong@vnu.edu.vnMinh Anh Vuvuminhanhhp@gmail.com2017-12-04T02:57:53Z2017-12-04T02:57:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2735This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/27352017-12-04T02:57:53ZCorona anemometry using dual pin probeIn this paper, we present an experimental study on the anemometry characteristics of a bipolar corona discharge probe with symmetrically arranged parallel electrodes. The possibility of measuring a wide range of air flow rate/flow velocity has been demonstrated. The parallel pin probe simultaneously creates positive and negative corona discharge, decomposes air media at both electrodes while keeping them with charge balance ensured by the use of a single isolated power source. This feature is fundamentally different from other reported unipolar discharge configurations, where the decomposed gas and charge is created from single electrode. Under the existence of the air flow, the decomposed gas is redistributed towards the downstream electrode, and changes the current–voltage characteristics of the system. When the probe is in open space, the discharge current is reduced with increasing flow velocity. In constrained space the discharge current behaviour is similar at high flow rates above 25 l min−1, while at low flow rates this relation is reversed. In addition, the sensitivity of discharge current to change in air flow is much higher when the negative pin is placed downstream. Both open space and constrained space characteristics are explained in terms of the influence of external flow on the ozone distribution and its effect on the discharge current. This explanation is supported by ozone measurements, with the data showing good correlation between the discharge current and ozone concentration with respect to the external flow. The role of the electrode separation and discharge voltage is also investigated.Van Thanh Dauvandt@gmail.comThien Xuan Dinhthien@cfd.ritsumei.ac.jpThanh Tung Buitungbt@vnu.edu.vnTibor Terebessytibor.terebessy@clearviewtraffic.com2017-11-16T04:33:06Z2017-11-16T04:33:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2661This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/26612017-11-16T04:33:06ZPOLYESTER KNIT-FABRICS TREATED WITH CATIONIC DIRECT DYES USING PLASMA -INDUCED GRAFT-POLYMERIZATIONPolyester knit-fabrics were treated by argon-helium plasma at room temperature and ambient pressure, subsequently graft-polymerized with acrylic acid in vapor. Plasma interaction to the polyester fibres and graft-polymerization of carboxyl functional groups were investigated. Finally, the polyester knit-fabric grafted with carboxyl groups were treated with cationic direct dyes at around 800C and ambient pressure. Results obtained show that grafted surface of the knit fabrics was dyed with the red color, and then their color surface becomes dark pink while their untreated surface has pinkish white. The graft polymerization of the carboxyl groups and the absorption of cationic direct dyes will be discussed in details.
Keywords: plasma-induced graft-polymerization, polyester-fiber knit-fabrics, cationic direct dyes, polyesterKien Cuong Nguyencuongnk@vnu.edu.vnSeiichi Kataoka2017-10-29T03:19:53Z2017-10-29T03:19:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2585This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/25852017-10-29T03:19:53ZManagement of solar energy in microgrids using IoT-based dependable controlSolar energy generation requires efficient monitoring and management in moving towards technologies for net-zero energy buildings. This paper presents a dependable control system based on the Internet of Things (IoT) to control and manage the energy flow of renewable energy collected by solar panels within a microgrid. Data for optimal control include not only measurements from local sensors but also meteorological information retrieved in real-time from online sources. For system fault tolerance across the whole distributed control system featuring multiple controllers, dependable controllers are developed to control and optimise the tracking performance of photovoltaic arrays to maximally capture solar radiation and maintain system resilience and reliability in real time despite failures of one or more redundant controllers due to a problem with communication, hardware or cybersecurity. Experimental results have been obtained to evaluate the validity of the proposed approach.Manh Duong Phungduongpm@vnu.edu.vnMichel VillefromoyQuang Haquang.ha@uts.edu.au2017-07-24T04:00:09Z2017-07-24T04:00:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2561This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/25612017-07-24T04:00:09ZAnnual Scientific Report 2017 (ASR 2017)The VNU-UET Annual Scientific Report has been started from 2016.Xuan Tu Trantutx@vnu.edu.vnXuan Hieu Phanhieupx@vnu.edu.vnDuc Tan Trantantd@vnu.edu.vnManh Thang Phamthangpm@vnu.edu.vnDuc Thang Phampdthang@vnu.edu.vnBao Son Phamsonpb@vnu.edu.vn2017-05-23T08:34:34Z2017-05-23T08:34:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2463This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24632017-05-23T08:34:34ZNonlinear dynamic response of eccentrically stiffened FGM plate using Reddy’s TSDT in thermal environmentThe nonlinear dynamics of an eccentrically stiffened functionally graded material (ES-FGM) plates resting on the elastic Pasternak foundations subjected to mechanical and thermal loads is considered in this article. The plates are reinforced by outside stiffeners with temperature-dependent material properties in two cases: uniform temperature rise and through the thickness temperature gradient. Both stiffeners and plate are deformed under temperature. Using Reddy’s third-order shear deformation plate theory, stress function, Galerkin and fourth-order Runge–Kutta methods, the effects of material and geometrical properties, temperature-dependent material properties, elastic foundations, and stiffeners on the nonlinear dynamic response of the ES-FGM plate in thermal environments are studied and discussed. Some obtained results are validated by comparing with those in the literature.Hong Cong PhamMinh Anh Vuvuminhanhhp@gmail.comDinh Duc Nguyenducnd@vnu.edu.vn2017-03-10T03:34:42Z2017-03-10T03:34:42Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2439This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24392017-03-10T03:34:42ZStudy of determination adjusted ratio for calculating strength of orthotropic laminated composite plates used in building shipVan Thu PhamVan Binh TrinhTan Dat HuynhVan Dat NguyenDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:38:02Z2017-03-06T04:39:21Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2438This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24382017-03-06T04:38:02ZThe mechanical effect and physics properties of ZnO nanoparticles in nanocomposite organic solar cell P3HT:PCBMDinh Duc Nguyenducnd@vnu.edu.vnDinh Long Dangddlong@vnu.edu.vnXuan Nguyen Nguyen2017-03-06T04:37:52Z2017-03-06T04:37:52Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2437This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24372017-03-06T04:37:52ZHybrid Phase Field Simulation of Dynamic Crack Propagation in Functionally Graded Glass-Filled EpoxyHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vnFushinobu Kazuyoshi2017-03-06T04:36:48Z2017-03-06T04:37:14Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2436This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24362017-03-06T04:36:48ZNonlinear stability analysis of imperfect three-phase sandwich laminated polymer nanocomposite panels resting on elastic foundations in thermal environmentsVan Thu PhamDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:34:41Z2017-05-23T08:35:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2435This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24352017-03-06T04:34:41ZVibration and nonlinear dynamic analysis of imperfect thin eccentrically stiffened functionally graded plates in thermal environmentsHong Cong PhamDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:29:03Z2017-03-06T04:29:36Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2433This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24332017-03-06T04:29:03ZAnalytical approach for investigating the nonlinear dynamic response of imperfect shear deformable FGM cylindrical panel subjected to blast loadsDinh Duc Nguyenducnd@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan Tran2017-03-06T04:28:17Z2017-03-06T04:28:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2432This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24322017-03-06T04:28:17ZNonlinear thermal dynamic analysis of pienzoelectric functionally graded platesDinh Duc Nguyenducnd@vnu.edu.vnPhuong TranHong Cong Pham2017-03-06T04:28:06Z2017-03-06T04:28:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2431This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24312017-03-06T04:28:06ZNonlinear stability of pienzoelectric functionally graded circular cylindrical shell under temperatureDuc Tuan NgoPhuong TranDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:25:53Z2017-03-06T04:25:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2430This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24302017-03-06T04:25:53ZNonlinear vibration and dynamic response of imperfect eccentrically stiffened shear deformable sandwich plate with functionally graded material in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDuc Tuan NgoPhuong Tran2017-03-06T04:25:24Z2017-03-06T04:25:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2429This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24292017-03-06T04:25:24ZNonlinear vibration and dynamic response of shear deformable imperfect functionally graded double curved shallow shells resting on elastic foundations in thermal environmentsQuoc Quan TranDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:25:02Z2017-03-06T04:25:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2428This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24282017-03-06T04:25:02ZNonlinear dynamic response and vibration of an imperfect three-phase laminated nanocomposite cylindrical panel resting on elastic foundations in thermal environments.Van Thu PhamDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:24:25Z2017-03-06T04:24:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2427This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24272017-03-06T04:24:25ZThermal stability analysis of eccentrically stiffened Sigmoid – FGM plate with metal –ceramic-metal layers based on FSDTHong Cong PhamDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:24:19Z2017-03-06T04:24:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2426This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24262017-03-06T04:24:19ZNonlinear thermo-mechanical dynamic analysis and vibration of higher order shear deformable piezoelectric functionally graded material sandwich plates resting on elastic foundationsDinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2017-03-06T04:24:10Z2017-03-06T04:24:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2425This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24252017-03-06T04:24:10ZNonlinear thermo-electro-mechanical dynamic response of shear deformable piezoelectric Sigmoid functionally graded sandwich circular cylindrical shells on elastic foundationsDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:24:00Z2017-03-06T04:24:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2424This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24242017-03-06T04:24:00ZNonlinear thermal dynamic analysis of eccentrically stiffened S-FGM circular cylindrical shells surrounded on elastic foundations using the Reddy’s third-order shear deformation shell theoryDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:23:49Z2017-03-06T04:23:49Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2420This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24202017-03-06T04:23:49ZHybrid Phase Field Simulation of Dynamic Crack Propagation in Functionally Graded Glass-Filled EpoxyHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vnFushinobu Kazuyoshi2017-03-06T04:23:38Z2017-03-06T04:23:38Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2419This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24192017-03-06T04:23:38ZEvaluation of elastic properties and thermal expansion coefficient of composites reinforced by randomly distributed spherical particles with negative Poisson’s ratiosThe Duong NguyenDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:23:25Z2017-03-06T04:23:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2418This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24182017-03-06T04:23:25ZEffects of variable thickness and imperfection on nonlinear buckling of Sigmoid-functionally graded cylindrical panelsToan Thang PhamDinh Duc Nguyenducnd@vnu.edu.vnThoi Trung Nguyen2017-03-06T04:23:11Z2019-01-14T02:54:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2417This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24172017-03-06T04:23:11ZNonlinear dynamic response and vibration of sandwich composite plates with negative Poisson’s ratio in auxetic honeycombsAuxetic cellular solids in the forms of honeycombs under blast load have great potential in a diverse range of applications, including core material in sandwich plates composite components. Based on Reddy’s first-order shear deformation plate theory, this paper presents an analysis of the nonlinear dynamic response and vibration of sandwich plates with negative Poisson’s ratio in auxetic honeycombes on elastic foundations subjected to blast and mechanical loads. A three-layer sandwich plate is considered discretized in the thickness direction by using analytical methods (stress function method, approximate solution), Galerkin method, and fourth-order Runge-Kutta method. The results show the effects of geometrical parameters, material properties, mechanical and elastic foundations on the nonlinear dynamic response, and vibration of sandwich plates.Dinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2017-03-06T04:22:44Z2017-03-06T04:22:44Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2416This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24162017-03-06T04:22:44ZEnhancement of energy conversion efficiency in organic solar cell using nanoparticlesDinh Duc Nguyenducnd@vnu.edu.vn2017-03-06T04:22:24Z2017-03-06T04:22:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2415This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24152017-03-06T04:22:24ZNanocompositematerials for energy conversion and storageDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:09:20Z2017-02-28T09:09:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2453This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24532017-02-28T09:09:20ZA Numerical Study of Mixed-mode Crack Propagation in ZnO2/NiCr Functionally Graded Materials by A Hybrid Phase-Field MethodMinh Phuc PhamHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiXuan Nguyen NguyenMinh Dung NguyenBinh Khiem NguyenDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:09:10Z2017-02-28T09:09:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2452This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24522017-02-28T09:09:10ZDynamics Crack Propagation Simulation by A Rate-dependent Phase Field Fracture ApproachHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiXuan Nguyen NguyenFushinobu KazuyoshiDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:08:50Z2017-02-28T09:08:50Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2451This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24512017-02-28T09:08:50ZA finite Element Model Using a New Third-order Shear Deformation Plate Theory for The Analysis of Heated Functionally Graded plates in High TemperatureVan Thom DoQuoc Tinh BuiHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:08:32Z2017-02-28T09:08:32Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2450This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24502017-02-28T09:08:32ZBuckling anslysis of plates with crack using FSDT and the phase-field theoryVan Thom DoHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:08:02Z2017-02-28T09:08:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2449This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24492017-02-28T09:08:02ZThe behavior of cracks in the interface ZnO2 / NiCrHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:07:45Z2017-02-28T09:07:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2448This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24482017-02-28T09:07:45ZApplying dynamic downscaling method with a high-resolution regional climate model for local climate projection in greater Hanoi cityQuang Van DoanKusaka HiroyukiMinh Truong NguyenHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vn2017-02-28T09:07:16Z2017-02-28T09:07:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2447This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24472017-02-28T09:07:16ZNonlinear buckling and postbuckling of an eccentrically stiffened E-FGM plate resting on elastic foudations in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamXuan Tinh Ho2017-02-28T09:07:07Z2017-02-28T09:07:07Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2446This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24462017-02-28T09:07:07ZNonlinear buckling and postbuckling of an eccentrically stiffened E-FGM circular cylindrical shells resting on elastic foundations in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan TranDinh Nguyen Pham2017-02-28T09:06:55Z2017-02-28T09:06:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2445This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24452017-02-28T09:06:55ZNonlinear dynamic response and vibration of imperfect eccentrically stiffened E-FGM double curved shallow shells in thermal environmentsDinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan Tran2017-02-28T09:06:39Z2017-02-28T09:06:39Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2444This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24442017-02-28T09:06:39ZNonlinear dynamic and vibration analysis of an eccentrically stiffened E-FGM plate in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDinh Dat Ngo2017-02-28T09:06:24Z2017-02-28T09:06:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2442This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24422017-02-28T09:06:24ZOn the nonlinear dynamic and vibration stability of S-FGM spherical shells with metal-ceramic-metal layers resting on elastic foundationDinh Duc Nguyenducnd@vnu.edu.vnThuy Anh VuDinh Quang Vuquangvd2510@gmail.com2017-02-28T09:05:58Z2017-02-28T09:05:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2441This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24412017-02-28T09:05:58ZNumerical Failure Simulation of Quasi-Brittle Materials using A Second-Order Implicit Gradient Damage TheoryQuoc Tinh BuiA.H Tuan NguyenHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vnHirose Sohichi2017-02-28T09:05:40Z2017-02-28T09:05:40Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2440This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24402017-02-28T09:05:40ZNonlinear dynamic and vibration analysis of imperfect eccentrically stiffened E-FGM circular cylindrical shells surrounded by Pasternak elastic foundation in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDuy Khanh Nguyen2017-02-28T08:25:41Z2017-02-28T08:25:41Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2422This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24222017-02-28T08:25:41ZNonlinear stability of eccentrically stiffened S-FGM elliptical cylindrical shells in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoPhuong TranHong Cong PhamDinh Nguyen Pham2017-02-28T08:25:32Z2017-02-28T08:25:32Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2421This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24212017-02-28T08:25:32ZNonlinear dynamic and vibration analysis of piezoelectric eccentrically stiffened FGM plates in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDinh Quang Vuquangvd2510@gmail.com2017-02-06T15:50:58Z2017-02-06T15:50:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2409This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/24092017-02-06T15:50:58ZThe nonlinear dynamic and vibration of the S-FGM shallow spherical shells resting on an elastic foundations including temperature effectsThis study investigated the nonlinear dynamic and vibration of the S-FGM shallow spherical shells with ceramic-metal-ceramic layers (in two cases: non-axisymmetric and axisymmetric shells) on an elastic foundations (EF) with different types of boundary conditions in thermal environment. Material compositions of the shell are graded in the thickness direction according to a sigmoid law distribution in terms of the volume fractions of the constituents. The governing equations are derived by using the classical shell theory and Pasternak's two parameters EF. The motion equations of dynamic analysis are determined due to Galerkin method and the obtained equation is numerically solved by using Runge–Kutta method. The approximate solutions are assumed to satisfy the different types of boundary conditions. The criterion suggested by Budiansky–Roth is applied to determine the dynamic critical buckling load and the nonlinear dynamic response is found by numerical form. In numerical results, the effects of geometrical parameters, material properties, the EF, boundary conditions, mechanical loads and temperature on the nonlinear dynamic and vibration stability of the shells are investigated.Dinh Duc Nguyenducnd@vnu.edu.vnDinh Quang Vuquangvd2510@gmail.comThi Thuy Anh Vuanhvutt@vnu.edu.vn2017-01-05T02:42:24Z2017-01-05T02:42:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2353This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23532017-01-05T02:42:24ZHigh accuracy electronic compass for detecting azimuth direction based on a novel magnetoelectric effectMost navigation systems today use compass to determine heading direction based on determining the earth’s magnetic fields in a horizontal plane. There are several types of electronic compasses based on different effects such as fluxgate, magnetoresistive, and magnetoinductive. This paper presents a novel electronics compassing for navigation system, a modification of the conventional magnetic compass, which based on magnetoelectric effect. Recent researches have shown that thanks to enhancement of shape magnetic anisotropy of Metglas ribbon, an high magnetic sensitivity (~Voltage/Tesla), and extremely high accurary (1 nanoTesla) geomagnetic sensors based on Metglas/PZT magnetoelectric laminate were built [1]. By intergrating 2-axis sensor with an electronic circuit and 12-bit ADC (Fig. 1), a high resolution magnetoelectric compass containing anplifcation, automatic degaussing, offset cancellation that enables 0.1 degree compass heading accuracy. This kind of magnetoelectric compass would contribute to the most sensitive and high accuracy electronic compass available in the industry todayThi Huong Giang Dogiangdth@vnu.edu.vnHuu Duc Nguyenducnh@vnu.edu.vn2017-01-05T02:39:45Z2017-01-05T02:39:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2345This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23452017-01-05T02:39:45ZStress Electro-Cardiogram Instrumentation: Principles and StructureElectrocardiography, nowadays, is an essential part of the initial evaluation for patients presenting with cardiac complaints. However, an normal electrocardiography can not eliminate absolutely the heart disease. For example, in the case our heart rate is irregular and appears intermittently, if ECG is mearsured between the attacks, it will be normally. Also, not all cases of myocardial infarction were detected by normal ECG and angina is a typical case. At that time, we will need to consider a special ECG – Stress (Exercise) Echocardiography. Stress echo is done as part of a stress test. During a stress test, patients exercise or take medicine (given by doctor) to make their heart work hard and beat fast. A technician will use echo to create pictures of patients’ heart before they exercise and as soon as they finish. Some heart problems, such as coronary heart disease, are easier to diagnose when the heart is working hard and beating fast. To meet the demands of this procedure, a stress electro-cardiogram instrumentation wil be used in order to observe and store the whole process. Generally, such this system consists of three main units: exercise equipment (treadmill/stationary bicycle), special ECG device and a supported computer system. By considering appropriate components, a stress ECG instrumentation can be designed and integrated completely.Manh Thang Phamthangpm@vnu.edu.vnNgoc Viet Nguyenvietnn@vnu.edu.vnVan Manh Hoangmanhhv87@vnu.edu.vnNgoc Linh Nguyennlnguyen@vnu.edu.vn2017-01-05T02:35:29Z2017-01-05T02:35:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2363This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23632017-01-05T02:35:29ZMô hình nứt nẻ liên tục (CFM) cho các vỉa nứt nẻ và áp dụng cho tầng móng mỏ Bạch HổCác vỉa nứt nẻ được mô hình hóa thành các mô hình nứt nẻ liên tục (CFM) với các thông số đặc trưng là mật độ và độ mở nứt nẻ trung bình. Các phương pháp Fuzzy logic và trí tuệ nhân tạo (ANN) được phát triển để xác định thông số mô hình CFM trên lưới địa chất toàn vỉa thông qua các thuộc tính địa chấn và các dữ liệu tại các giếng. Dữ liệu khảo sát tại giếng dùng để xác định các thông số cho mô hình tại các ô lưới chứa giếng. Thuật toán Fuzzy logic dùng để đánh giá tương giữa các thuộc tính địa chấn và các thông số của mô hình CFM. Thuật toán ANN được sử dụng để xác định quan hệ giữa các thuộc tính địa chấn và thông số của mô hình CFM tại các ô giếng, sau đó thác triển các thông số này cho toàn vỉa. Các chương trình tính toán của mô hình được viết bằng ngôn ngữ FORTRAN. Kết quả đã được kiểm tra và thử nghiệm áp dụng để xác định độ thấm cho tầng móng mỏ Bạch Hổ và cho kết quả tốt.The Ba Dangbadt@vnu.edu.vnQuang Thai Nguyen2017-01-05T02:33:16Z2017-01-05T02:33:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2285This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22852017-01-05T02:33:16ZOn the nonlinear stability of eccentrically stiffened functionally graded annular spherical segment shellsDinh Duc Nguyenducnd@vnu.edu.vnHuy Bich DaoThi Thuy Anh Vuanhvutt@vnu.edu.vn2017-01-05T02:31:33Z2017-01-05T02:31:33Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2282This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22822017-01-05T02:31:33ZOn the linear stability of eccentrically stiffened functionally graded annular spherical shell on elastic foundationsThi Thuy Anh Vuanhvutt@vnu.edu.vnHong Cong PhamHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2017-01-04T07:21:16Z2017-01-04T07:21:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2246This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22462017-01-04T07:21:16ZFluidic lens by using thermal lens effectHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnYoshihiko AkamineKazuyoshi Fushinobu2017-01-04T07:20:40Z2017-01-04T07:20:40Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2245This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22452017-01-04T07:20:40ZFinite-Difference Time Domain Analysis of Ultrashort Pulse Laser Light Propagation under Nonlinear CouplingYoshihiko AKAMINEHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi FUSHINOBU2017-01-04T07:20:02Z2017-01-04T07:20:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2244This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22442017-01-04T07:20:02ZGeneration of Bessel Beam by Using Thermal LensHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnYoshihiko AKAMINENaoki IWATANIMasamichi KOHNOKazuyoshi FUSHINOBU2017-01-04T07:19:27Z2017-01-04T07:19:27Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2243This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22432017-01-04T07:19:27ZFundamental investigation of fluidic optical devices: Transmission characteristics of laser beam in 1D temperature field of liquid mediumHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi FushinobuKen Okazaki2017-01-04T07:18:57Z2017-01-04T07:18:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2239This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22392017-01-04T07:18:57ZOptimization of near-infrared laser drilling of silicon carbide under waterNaoki IwataniHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi Fushinobu2017-01-04T07:18:24Z2017-01-04T07:18:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2222This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22222017-01-04T07:18:24ZInfluence of natural convection on beam propagation in fluidic optical deviceByunggi KimHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi Fushinobu2017-01-04T03:26:58Z2017-01-04T03:26:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2221This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22212017-01-04T03:26:58ZOn the thermal buckling analysis of functionally graded plates with internal defects using extended isogeometric analysisTiantang YuQuoc Tinh BuiShuohui YinHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnC.T. WuVan Thom DoSatoyuki Tanaka2017-01-04T03:25:53Z2017-01-04T03:25:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2220This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22202017-01-04T03:25:53ZBessel beam laser-scribing of thin film silicon solar cells by ns pulsed laserHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnRyoichi IIDAByunggi KIMIsao SATOHKazuyoshi FUSHINOBU2016-12-31T14:32:56Z2016-12-31T14:32:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2347This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23472016-12-31T14:32:56ZResearch on improving aerodynamic performance of an UAV airfoil using numerical simulation methodThis paper shows research results which allow improving the aerodynamic performance of an UAV airfoil through the modeling and simulation of aerodynamic flow around an airfoil using Computational Fluid Dynamics (CFD) tools. Firstly, a model of wing with the NACA4415 across area is considered under the effect of low speed air flow at different coming angles. The aerodynamic characteristics of this airfoil will be simulated, calculated and analyzed. Based on the analysis, the author proposes a new design of UAV airfoil in order to improve the aerodynamic performance of the wing. Several profiles of proposed design have been investigated in the similar airstream conditions with respect to the initial one by using the numerical simulation method on COMSOL software. The results show the good response of the new design. This research can apply for the design and construction tasks about unmanned aerial vehicle (UAV) in Vietnam.Ngoc Viet Nguyenvietnn@vnu.edu.vnVan Manh Hoangmanhhv87@vnu.edu.vnNgoc Linh Nguyennlnguyen@vnu.edu.vn2016-12-31T14:23:58Z2017-01-13T02:26:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2253This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22532016-12-31T14:23:58ZA survey for wireless sensor network applicationsWireless Sensor Networks (WSNs) are an emerging technology for low-cost with vital applications such as unattended monitoring of a wide range of environmental parameters and target tracking. This has been enabled by the availability, particularly in recent years, of sensors that are smaller, cheaper, and intelligent. These sensors are equipped with wireless interfaces that they can communicate with one another to create a network. The design of a WSN depends significantly on the applications, and it must consider factors such as the environment, the application’s design objectives, cost, hardware, and system constraints. This work not only discusses about their potential advantages and disadvantages but also gives an overview of several new applications and identifies the research challenges associated with such applications.
Key Words: Wireless sensor networks; Sensor network services; ZigBee; Sensor network deployment.Thai Son Transon.th.tran@gmail.comVan Manh Hoangmanhhv87@vnu.edu.vnManh Thang Phamthangpm@vnu.edu.vn2016-12-31T14:13:53Z2016-12-31T14:13:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2219This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22192016-12-31T14:13:53ZOn the high temperature mechanical behaviors analysis of heated functionally graded plates using FEM and a new third-order shear deformation plate theoryQuoc Tinh BuiVan Thom DoLan Hoang That TonHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnSatoyuki TanakaDat Tien PhamThien-An Nguyen-VanTiantang YuSohichi Hirose2016-12-31T14:12:06Z2016-12-31T14:12:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2218This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22182016-12-31T14:12:06ZHybrid phase field simulation of dynamic crack propagation in functionally graded glass-filled epoxyHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnQuoc Tinh BuiDinh Duc Nguyenducnd@vnu.edu.vnKazuyoshi Fushinobu2016-12-31T14:10:55Z2016-12-31T14:10:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2217This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22172016-12-31T14:10:55ZHigh frequency modes meshfree analysis of Reissner–Mindlin platesQuoc Tinh BuiHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnVan Thom DoSohichi HiroseDinh Duc Nguyenducnd@vnu.edu.vn2016-12-31T14:09:17Z2016-12-31T14:09:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2216This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22162016-12-31T14:09:17ZMechanism of TCO thin film removal process using near-infrared ns pulse laser: Plasma shielding effect on irradiation directionByunggi KimRyoichi IidaHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi Fushinobu2016-12-31T14:08:09Z2016-12-31T14:08:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2215This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22152016-12-31T14:08:09ZEnhanced nodal gradient 3D consecutive-interpolation tetrahedral element (CTH4) for heat transfer analysisMinh Ngoc NguyenQuoc Tinh BuiThien Tich TruongNgoc Anh TrinhIndra Vir SinghTiantang YuHong Duc Doandoan.hd.amsl.eng@vnu.edu.vn2016-12-31T14:06:47Z2016-12-31T14:06:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2214This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22142016-12-31T14:06:47ZNumerical modeling of 3-D inclusions and voids by a novel adaptive XFEMZhen WangTiantang YuQuoc Tinh BuiNgoc Anh TrinhThi Hien Luong NguyenDinh Duc Nguyenducnd@vnu.edu.vnHong Duc Doandoan.hd.amsl.eng@vnu.edu.vn2016-12-31T14:05:15Z2016-12-31T14:05:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2213This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22132016-12-31T14:05:15ZNanosecond pulse laser scribing using Bessel beam for single shot removal of transparent conductive oxide thin filmByunggi KimRyoichi IidaHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi Fushinobu2016-12-31T10:19:45Z2016-12-31T10:19:45Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2207This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22072016-12-31T10:19:45ZNonlinear response of a shear deformable SFGM shallow spherical shell with ceramic-metalceramic layers resting on an elastic foundation in a thermal environmentThis article presents an analytical approach to investigate the nonlinear stability of thick, functionally graded material (FGM) shallow spherical shells resting on elastic foundations, subjected to uniform external pressure and exposed to thermal environments. Material properties are assumed to be temperature dependent and graded in the thickness direction according to a Sigmoid power law distribution (S-FGM) in terms of the volume fractions of constituents. Using the first-order shear deformation theory and the Galerkin method, the effects of materials, geometry, elastic foundation parameters, and temperature on the nonlinear response of the thick S-FGM shells are analyzed and discussed in detail.Thi Thuy Anh Vuvuanhthuy206@gmail.comDinh Duc Nguyenducnd@vnu.edu.vn2016-12-31T10:12:13Z2016-12-31T10:12:13Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2349This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23492016-12-31T10:12:13ZA New Approach to Predictive Control a Permanent Magnet Synchronous Motor fed by a Matrix ConverterIn this paper, a new approach to predictive control for speed control of a permanent magnet synchronous motor fed by a matrix converter is presented. The principle of this approach is to extend the possibilities of control by offering additional virtual vectors and to find the vector which minimizes the cost function. This process includes two main steps: first one will determine the location of vector in space vector and the second one will calculate the module of this voltage vector. In detail, a discrete mathematic model of drive system is built to predict the behaviors in the next step under a set of finite control states (FCS). This set will include not only eight real voltage vector from a three-phase two-level matrix converter but also the virtual voltage vectors. Predictive controller optimizes a predefined cost function in order to find a voltage vector giving the best result. Space vector modulation (SVM) technique will be used to generate the found voltage vector. The whole system has been modeled and simulated by using MATLAB and SIMULINK software to verify the performance of proposed method under different load and speed conditions. Results also are compared with classic direct predictive control about fundamental value and total harmonic distortion (THD) to highlight the improvement.Ngoc Linh Nguyennlnguyen@vnu.edu.vn2016-12-31T10:11:21Z2016-12-31T10:11:21Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2382This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23822016-12-31T10:11:21ZDesigning and Analyzing of a Dual-Buoy 5kW Wave Energy ConverterOcean wave energy is a renewable energy source with a large potential to contribute to the world’s electricity production. The work presented in this article is intended to calculate and analyze a dual-buoy 5kW wave energy converter. This device consists of two-body point absorber, one floating body and one semi-submerged body, which moves inside a tube. A linear permanent magnet generator that is a direct-driven conversion mechanism connects two bodies. In this article, a simple modeling approach for the linear permanent magnet generator is presented and its structure is described.The Ba Dangbadt@vnu.edu.vnVan Tien DoanHoang Quan Nguyenquannh@vnu.edu.vn2016-12-31T10:09:19Z2016-12-31T10:09:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2348This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23482016-12-31T10:09:19ZA Study on Low-Speed Wind Tunnel – Theory and ExperimentA wind tunnel is an important tool used in aerodynamic field to investigate the effects of airstream moving through solid objects. In this paper, a low-speed wind tunnel with a cross section of 50250mm of working area and a free low velocity from 0 up to 27 m/s was considered. This model includes 30 differential pressure sensors, allows us to measure the pressure along the tunnel. In order to operate the system, a human-machine interface (HMI) in LabVIEW environment has been built. It allows us to modify the experimental parameters as well as display and collect the data. A number of tests with the model are carried out. The study shows that the results obtained from the experimental model are well agreed with the fluid dynamic theory. It shows that the low-speed wind tunnel proposed in this research can be used to study flow phenomena as well as to investigate the aerodynamic charateristics of testing objects.Minh Triet NguyenVan Long NguyenNgoc Viet NguyenNgoc Linh Nguyennlnguyen@vnu.edu.vnManh Thang Phamthangpm@vnu.edu.vn2016-12-31T10:08:05Z2016-12-31T10:08:05Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2386This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23862016-12-31T10:08:05ZDesigning and developing of a stabilizer for direct-driven wave energy converterThiết bị chuyển đổi năng lượng sóng biển cơ cấu trực tiếp dung máy phát tịnh tiến có ưu điểm đơn giản, độ tin cậy cao, dễ triển khai. Tuy nhiên, đặc trưng nguồn điện không ổn định cao là rào cản lớn nhất cho sự phát triển của thiết bị này trong thực tế. Phát triển bộ biến đổi, ổn định dòng điện cho đầu ra của các thiết bị phát điện từ các nguồn năng lượng tái tạo như sóng, gió, mặt trời…, với đặc trưng chung là đầu ra không ổn định, là nhu cầu cần thiết và đang được quan tâm nhiều trên thế giới và cả Việt Nam.
Báo cáo trình bày một số kết quả phát triển mô hình và thiết kế chế tạo bộ biến đổi điện đầu ra 3 pha cho máy phát điện tịnh tiến công suất 40W dung cho thiết bị chuyển đổi năng lượng sóng cơ cấu trực tiếp với máy phát điện tinh tiến. Từ các tham số đặc trưng đầu ra của máy phát điện đang phát triển, như biên độ điện áp, dòng điện đầu ra, đã xây dựng sơ đồ mạch nguyên lí, mô hình tính toán mô phỏng, thiết kế và phát triển mạch điện tử. Kết quả kiểm tra thực tế bằng thực nghiệm cho kết quả là nguồn điện ổn định một chiều 12V cho nhiều mục đích sử dụng khác nhau như nạp ắc quy, thắp đèn chiếu sáng và các dụng cụ điện công suất nhỏ. Nghiên cứu cũng là cơ sở cho tính toán thiết kế, chế tạo các bộ biến đổi ổn định điện công suất lớn hơn cho mục đích khai thác sử dụng năng lượng tái tạo, đặc biệt là năng lượng sóng.Van Duc NguyenThe Ba Dangbadt@vnu.edu.vnThang Long Nguyenlongnt@vnu.edu.vn2016-12-31T10:01:32Z2017-01-13T02:28:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2202This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22022016-12-31T10:01:32ZExtremum Seeking Control based MPPT for photovoltaic array under uniform and non-uniform irradiancesIn order to extract the maximum power from photovoltaic (PV) array, the maximum power point tracking (MPPT) technology has always been applied in PV systems. The Perturb and Observe (P&O) and Incremental Conductance (INC) methods are the most popular and widely used under the constant irradiance. However, the changes of the environmental parameters, such as cloud cover or the building block, will lead to the radiation change and then have a direct effect on the location of Maximum Power Point (MPP). In order to carry out MPPT in PV array under Partial Shading Conditions (PSCs), a method based on Extremum Seeking Control (ESC) is applied to determine the optimal value of a reference current in the PV system. The proposed ESC approach for the Global Maximum Power Point Tracking (GMPPT) in this work uses a series combination of a High Pass Filter (HPF) and two Low Pass Filters (LPFs). These three filters act as two Band Pass Filters (BPFs) and let a specific frequency of input power which includes the derivative of PV with respect to its voltage pass through. This auto-tuning strategy was developed to maximize the PV array output power through the regulation of the voltage input to the DC-DC boost converter in order to lead the PV array steady-state to a stable oscillation behavior around the Global Maximum Power Point (GMPP). The performance of the proposed ESC algorithm is evaluated by comparing it with the conventional ESC and modified P&O method in terms of tracking speed and accuracy by utilizing MATLAB SIMULINK. The simulation results demonstrate that the tracking capability of the proposed ESC algorithm is superior to that of the conventional ESC and modified P&O algorithm, particularly under low radiance and sudden mutation irradiance conditions.
Key Words: Boost converter; Extremum Seeking Control; Maximum Power Point Tracking (MPPT); Partial Shading Conditions (PSCs); Photovoltaic (PV) system.Van Manh Hoangmanhhv87@vnu.edu.vnNgoc Viet Nguyenvietnn.mt@gmail.comManh Thang Phamthangpm@vnu.edu.vn2016-12-31T09:56:50Z2016-12-31T09:56:50Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2367This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23672016-12-31T09:56:50ZModeling an Testing of a Two-buoy Heaving Wave Energy ConverterA design of a two-buoy small scale point absorber was built and tested in July 2016 on West Lake. The tests were aimed at performance characterization and validation of a linear dynamics model. The coefficients used in the model are obtained through a combination of bench-top and tank-side experiment. The device produced an average of 40W from waves of 35 cm height and frequencies between 0.6-0.8Hz. The experimental results compare reasonably well with the numerical model. However, there is a significant amount of scatter in the experimental values which was attributed to various sourcesVan Ngoc PhungThe Ba Dangbadt@vnu.edu.vnVan Duc Nguyen2016-12-29T12:52:51Z2017-01-12T16:10:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2354This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/23542016-12-29T12:52:51ZA Novel Behavior-based Navigation Architecture of Mobile Robot in Unknown EnvironmentsThis study proposes behavior-based navigation architecture, named BBFM, for mobile robot in unknown environment with obstacles. The architecture is carried out in three steps: (i) analyzing the navigation problem to determine parameters of the architecture; (ii) designing the objective functions to relate input data with the desired output; and (iii) fusing the output of each objective function to generate the optimal control signal. We use fuzzy logic to design the objective functions and multi-objective optimization to find the Pareto optimal solution for the fusion. A number of simulations, comparisons, and experiments were conducted. The results show that the proposed architecture outperforms some popular behavior- based architectures in navigating the mobile robot in complex environments.Thi Thanh Van Nguyenvanntt@vnu.edu.vnManh Duong Phungduongpm@vnu.edu.vnAnh Viet Dangvietda@vnu.edu.vnQuang Vinh Tranvinhtq@vnu.edu.vn2016-12-27T07:18:34Z2016-12-27T07:18:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2287This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22872016-12-27T07:18:34ZNonlinear stability analysis of thin FGM annular spherical shells on elastic foundations under external pressure and thermal loadsThi Thuy Anh Vuvuanhthuy206@gmail.comHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2016-12-23T08:39:35Z2016-12-23T08:39:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2288This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22882016-12-23T08:39:35ZNonlinear axisymmetric response of FGM shallow spherical shells on elastic foundations under uniform external pressure and temperatureBased on the classical shell theory taking into account geometrical nonlinearity, initial geometrical imperfection and Pasternak type elastic foundation, the nonlinear axisymmetric response of shallow spherical FGM shells under mechanical, thermal loads and different boundary conditions is considered in this paper. Using the Bubnov–Galerkin method and stress function, obtained results show effects of elastic foundations, external pressure, temperature, material and geometrical properties on the nonlinear buckling and postbuckling of the shells. The snap-through behaviors of the FGM spherical shallow shells on elastic foundations also are analyzed carefully in this paper. Some results were compared with the ones of other authors.Dinh Duc Nguyenducnd@vnu.edu.vnThi Thuy Anh Vuanhvutt@vnu.edu.vnHong Cong Pham2016-12-23T04:08:01Z2016-12-23T04:09:38Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2289This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22892016-12-23T04:08:01ZThe nonlinear stability of axisymmetric functionally graded material annular spherical shells under thermo-mechanical loadThi Thuy Anh Vuanhvutt@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vn2016-12-19T03:19:15Z2016-12-19T03:19:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2263This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22632016-12-19T03:19:15ZLong-Term Energy Accumulation in Underground Hot Water Tanks: Fluid Convective Behaviour and Its Influence on the Thermal LossesMilan RashevskiHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi FUSHINOBU2016-12-19T02:40:09Z2016-12-19T02:40:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2264This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22642016-12-19T02:40:09ZFluidic Optical Devices Based on Thermal Lens EffectHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnFushinobu Kazuyoshi2016-12-17T15:56:42Z2016-12-17T15:56:42Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2262This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22622016-12-17T15:56:42ZFluidic laser beam shaper by using thermal lens effectHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnYoshihiko AkamineKazuyoshi Fushinobu2016-12-16T08:17:06Z2016-12-16T08:17:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2242This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22422016-12-16T08:17:06ZLaser processing by using fluidic laser beam shaperHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnIwatani NaokiFushinobu Kazuyoshi2016-12-16T08:16:10Z2016-12-16T08:16:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2241This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22412016-12-16T08:16:10ZA study of near-infrared nanosecond laser ablation of silicon carbideHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnIwatani NaokiFushinobu Kazuyoshi2016-12-16T08:14:52Z2016-12-16T08:14:52Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2240This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/22402016-12-16T08:14:52ZPulse-shaping of nanosecond pulse laser by means of thermal lens effectByunggi KIMRyota INOUEHong Duc Doandoan.hd.amsl.eng@vnu.edu.vnKazuyoshi FUSHINOBU2016-12-04T13:44:22Z2017-01-17T02:46:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2062This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/20622016-12-04T13:44:22ZThe 2016 Annual Scientific Report of VNU University of Engineering and TechnologyThe University of Engineering and Technology (UET) was founded in 2004 as a member university of Vietnam National University, Hanoi (VNU).
The last only five years have seen immense progresses in the development of our university in various aspects of its activities thanks to the great efforts put in by the government with strong financial supports, by the VNU with steering leadership and administration, by the national and international educational institutions and corporations in fruitful collaborations and advices, and by all the staff and students of the UET with determination, hard work and patience.
Today, our university has built up a solid foundation for a sustainable and dynamic development in coming years. This solid foundation consists of a completed system of well-designed programs at both undergraduate and graduate levels, renovated teaching and learning facilities, a just limited but strong and advanced research infrastructure with state-of-the-art and completed equipment systems, a sustainable and fruitful collaboration with leading research and educational institutions in the country, and a bright, young, well-educated and welltrained faculty who are eager to take on advanced research and studies. All these have made our university a prestigious institution and firmly established its education and research capabilities. This is proved by the facts that only in the last four years our university has established close and solid ties and cooperation with prestigious foreign universities, just to name a few, the University Paris-Sud 11 (France), Japan Advanced Institute of Science and Technology, the National University of Singapore, Nanyang Technological University (Singapore), University of New South Wales and with famous international industrial and technological corporations such as Samsung, Toshiba, NEC, Mitani, Human Resocia, IBM, and other well-known institutions in the region and around the world. This is also proved in a convincing way by the facts that only in the last two years, our university has been granted several significant research projects from various national research programs. Our university has become an attractive destination for talented students at all training levels. We are proud that our university is the only Vietnamese higher-education institution that has one among the 100 best student’s teams all over the world participating the World Final of the ACM International Collegiate Programming Contest (rank #29 in 2015). We are also proud that in this year, our faculty has won an award in the National Contest in Information Technology entitled “Vietnamese Talent Award” and three awards in the VNU Science & Technology Award for the period of 2011-2015. In the coming period, we shall put our great efforts to solidify our strength and prestige. We shall widen our training scope while paying significant attention to further improvement on the education quality. We shall strongly enhance our concentrated research activity by exploring efficiently and effectively our well established foundation for a further dynamic development and, thus, contributing our crucial part to the socio-economic development of our nation and fulfilling our great missions clearly assigned by the government in the decision on the establishment of our university. To do that, innovative thinking and acting by all faculty, administrative staff and students are of deciding role and of crucial importance.Xuan Tu Trantutx@vnu.edu.vnAnh Cuong Lecuongla@vnu.edu.vnDuc Tan Trantantd@vnu.edu.vnManh Thang Phamthangpm@vnu.edu.vnThi Huong Giang Dogiangdth@vnu.edu.vn2016-07-18T03:21:28Z2016-07-18T03:21:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1794This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17942016-07-18T03:21:28ZUltrasonic Doppler velocity profile measurement of single- and two-phase flows using spike excitationIn the article, the application of the electrical spike, instead of the tone-burst, to the ultrasonic pulsed-Doppler velocity profiling the first time is presented. To generate ultrasound, the ultrasonic sensor is excited by the spike. For the Doppler method, the spike excitation was not used previously. It has been used with wideband signal processing methods. In our study, first, the fluid-velocity profile measurement using spike excitation has been carried out for single-phase pipe flow. The received data have been validated by the logarithmic law of the wall, for turbulent flow regime. The flow rate calculated by using the mean velocity profile well coincides with the flow-meter data. Furthermore, the spike signal and the Doppler method are used in the multiwave ultrasonic velocity profile (UVP) method, for the bubbly flow measurement. The experiments show that, if the spike signal is slowly damped, the generated ultrasonic wave is similar to the tone-burst that is required for the Doppler method, but in this case, usually the pulse length is smaller and depends on the damping and sensor characteristics. The autocorrelation technique is used for echo signal processing. The derived UVP systems inherit the advantages from both the spike excitation and Doppler method.Tat Thang NGUYENHideki MURAKAWANobuyoshi TSUZUKINgoc Hai DUONGHiroshige KIKURA2016-07-13T10:01:43Z2016-07-13T10:02:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1793This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17932016-07-13T10:01:43ZMeasurement of the condensation rate in subcooled flow boiling by using two ultrasonic frequenciesTat Thang NguyenTSUZUKI NobuyoshiMURAKAWA HidekiNgoc Hai DuongKIKURA Hiroshige2016-07-11T12:24:58Z2016-07-11T12:51:18Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1791This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17912016-07-11T12:24:58ZDynamic analysis of a cracked beam-like bridge subjected to earthquake and moving vehicleThis paper presents the influence of a crack on the dynamic behavior of a beam-type bridge subjected to separately or simultaneously a moving vehicle and earthquake excitation. In this study, the bridge is modelled as a 3D beam by the finite element method. The stiffness matrix of a cracked beam element with rectangular section adopted from fracture mechanics is presented. The influences of crack appearance time, crack location, crack depth, and vehicle speed on the dynamic response of the bridge are investigated. When a crack is induced during external excitation the stiffness of the structure is changed leading to a change in natural frequencies during vibration. This change in the frequency is analysed by wavelet spectrum, a time-frequency analysis which can examine locally a signal in both time and frequency domains. The relationship between the crack depth and the instantaneous frequency (IF) of the structure is established which may prove useful for assessment of the crack depth. Numerical simulation results are presented to investigate the efficiency of the method.Viet Khoa Nguyen2016-07-06T06:32:50Z2016-07-06T06:33:28Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1789This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17892016-07-06T06:32:50Z1/3 SUBHARMONIC RESPONSE OF DUFFING OSCILLATOR UNDER PERIODIC AND RANDOM EXCITATIONSDong Anh NguyenL. Zakovorotny V.N. Hao D.X. Chiem N.2016-07-06T06:32:06Z2016-07-06T06:32:37Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1787This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17872016-07-06T06:32:06ZGlobal–local mean square error criterion for equivalent linearization of nonlinear systems under random excitationThe paper presents a dual approach with respect to the local mean square error criterion to multi-degree-of-freedom nonlinear systems under stationary Gaussian random excitation. It results in new values of linearization coefficients that are obtained as global averaged values of all local linearization coefficients. Two examples of typical two-degree-of-freedom nonlinear systems under zero-mean stationary Gaussian random excitation are demonstrated. The results show that the accuracy of solutions by the proposed criterion is significantly improved in comparison with the one by the classical equivalent linearization method, especially when the nonlinearity is strong.Dong Anh NguyenX. Hung LeDuc Viet LaC. Thang Nguyen2016-07-06T03:52:33Z2016-07-06T03:53:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1790This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17902016-07-06T03:52:33ZMode shape analysis of a cracked beam and its application for crack detectionViet Khoa Nguyen2016-06-30T09:59:50Z2016-06-30T10:02:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1786This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17862016-06-30T09:59:50ZPartial Stochastic Linearization of a Spherical Pendulum With Coriolis Damping Produced by Radial Spring and DamperThis study considers the stochastic analysis of a spherical pendulum, whose bidirectional vibration is reduced by spring and damper installed in the radial direction between the point mass and the cable. Under sway motion, the centrifugal force results in the radial motion, which in its turn produces the Coriolis force to reduce sway motion. In stochastic analysis and design, the problem is that the Monte Carlo simulation is time-consuming, while the full stochastic linearization totally fails to describe the effectiveness of the spring and damper. We propose the partial linearization applied to the Coriolis damping to overcome the disadvantages of two mentioned methods. Moreover, the proposed technique can give the analytical solution of partial linearized system. A numerical simulation is performed to verify the proposed approach.Duc Viet La2016-05-28T04:00:28Z2016-05-28T04:00:28Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1695This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16952016-05-28T04:00:28ZNonlinear dynamic response of imperfect symmetric thin S-FGM plate with metal- ceramic-metal layers on elastic foundationDinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2016-05-26T15:33:13Z2016-05-26T15:33:44Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1693This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16932016-05-26T15:33:13ZNonlinear dynamic analysis and vibration of shear deformable piezoelectric FGM double curved shallow shells under damping-thermo-electro-mechanical loadsDinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan TranDinh Luat Vu2016-05-26T15:31:27Z2016-05-26T15:32:03Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1678This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16782016-05-26T15:31:27ZNonlinear vibration and dynamic response of shear deformable imperfect functionally graded double curved shallow shells resting on elastic foundations in thermal environmentsQuoc Quan TranDinh Duc Nguyenducnd@vnu.edu.vn2016-05-26T15:29:35Z2016-05-26T15:31:11Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1677This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16772016-05-26T15:29:35ZNonlinear dynamic analysis of Sigmoid functionally graded circular cylindrical shells on elastic foundations using the third order shear deformation theory in thermal environmentsDinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoPhuong TranTrong Dao NguyenTat Dat Ngo2016-05-26T09:01:00Z2016-05-26T09:01:50Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1676This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16762016-05-26T09:01:00ZThermal stability of eccentrically stiffened FGM plate on elastic foundation based on Reddy’s third-order shear deformation plate theoryDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDinh Quang Vuquangvd2510@gmail.com2016-05-26T08:58:29Z2016-05-26T08:59:13Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1697This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16972016-05-26T08:58:29ZNonlinear response of imperfect eccentrically stiffened ceramic-metal-ceramic S-FGM thin circular cylindrical shells surrounded on elastic foundations under uniform radial loadDinh Duc Nguyenducnd@vnu.edu.vnToan Thang Pham2016-05-26T08:50:30Z2016-05-26T08:52:26Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1694This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16942016-05-26T08:50:30ZNonlinear dynamic analysis and vibration of shear deformable eccentrically stiffened S-FGM cylindrical panels with metal-ceramic-metal layers resting on elastic foundationsQuoc Quan TranPhuong TranDuc Tuan NgoDinh Duc Nguyenducnd@vnu.edu.vn2016-05-26T06:23:52Z2016-05-26T06:25:25Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1699This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16992016-05-26T06:23:52ZNonlinear vibration of thick FGM plates on elastic foundation subjected to thermal and mechanical loads using the first order shear deformation plate theoryDinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2016-05-26T06:21:00Z2016-05-26T06:23:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1700This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17002016-05-26T06:21:00ZNonlinear analysis on flutter of FGM plates using Ilyushin supersonic aerodynamic theoryHong Cong PhamHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2016-05-26T02:53:43Z2016-05-26T02:55:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1692This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16922016-05-26T02:53:43ZNonlinear dynamic analysis of imperfect FGM double curved thin shallow shells with temperature-dependent properties on elastic foundationDinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan Tran2016-05-26T02:52:16Z2016-05-26T02:53:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1702This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17022016-05-26T02:52:16ZNonlinear stability of thin FGM annular spherical segment in thermal environmentThi Thuy Anh Vuvuanhthuy206@gmail.comHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2016-05-26T02:51:12Z2016-05-26T02:51:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1705This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17052016-05-26T02:51:12ZThermal stability analysis of eccentrically stiffened Sigmoid FGM plate with metal-ceramic-metal layers based on first-order shear deformation plate theoryDinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2016-05-26T02:50:07Z2016-05-26T02:50:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1704This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17042016-05-26T02:50:07ZNonlinear dynamic response of imperfect FGM plates subjected to blast loadDinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoPhuong TranQuoc Quan TranVan Quyen Nguyen2016-05-26T02:39:47Z2016-05-26T02:42:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1703This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17032016-05-26T02:39:47ZResearch on flutter of double curved thin FGM shallow shells on elastic foundations using Ilyushin nonlinear supersonic aerodynamic theoryQuoc Quan TranHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2016-05-26T02:38:39Z2016-05-26T02:39:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1708This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17082016-05-26T02:38:39ZCrane sway reduction using Coriolis force produced by radial spring and damperDuc Viet La2016-05-26T01:13:31Z2016-05-26T02:36:23Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1696This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16962016-05-26T01:13:31ZNonlinear buckling analysis of thin FGM annular spherical shells on elastic foundations under external pressure and thermal loadsThi Thuy Anh VuHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2016-05-25T14:19:21Z2016-05-25T14:20:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1701This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17012016-05-25T14:19:21ZNonlinear analysis on flutter of functional graded cylindrical panels on elastic foundations using the Ilyushin nonlinear supersonic aerodynamic theoryQuoc Quan TranHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2016-05-25T14:02:55Z2016-05-25T14:06:50Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1707This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/17072016-05-25T14:02:55ZA Cable-Passive Damper System for Sway and Skew Motion Control of a Crane SpreaderDuc Viet LaPark Youngjin2016-05-25T04:03:51Z2016-05-25T04:07:39Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1681This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16812016-05-25T04:03:51ZNonlinear vibration and dynamic response of imperfect eccentrically stiffened shear deformable sandwich plate with functionally graded material in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamDuc Tuan NgoPhuong TranMinh Anh Vuvuminhanhhp@gmail.comDinh Quang Vuquangvd2510@gmail.com2016-05-25T04:02:33Z2016-05-25T04:03:30Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1680This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16802016-05-25T04:02:33ZNonlinear mechanical, thermal and thermo-mechanical postbuckling of imperfect eccentrically stiffened thin FGM cylindrical panels on elastic foundationsDinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoQuoc Quan TranVan Quyen NguyenVan Anh Trananhtv0511@gmail.com2016-05-25T04:01:24Z2016-05-25T04:02:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1682This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16822016-05-25T04:01:24ZThe nonlinear stability of axisymmetric FGM annular spherical shells under thermo-mechanical loadThi Thuy Anh VuDinh Duc Nguyenducnd@vnu.edu.vn2016-05-25T03:59:33Z2016-05-25T04:00:59Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1683This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16832016-05-25T03:59:33ZMechanical and thermal stability of eccentrically stiffened functionally graded conical shell panels resting on elastic foundations and in thermal environmentDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamMinh Anh Vuvuminhanhhp@gmail.comDinh Quang Vuquangvd2510@gmail.comPhuong TranDuc Tuan NgoHoa Thinh Nguyen2016-05-25T03:45:44Z2016-05-25T03:52:06Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1687This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16872016-05-25T03:45:44ZNonlinear thermal dynamic response of shear deformable FGM plates on elastic foundationsDinh Duc Nguyenducnd@vnu.edu.vnHuy Bich DaoHong Cong Pham2016-05-25T03:33:45Z2016-05-25T03:35:07Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1686This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16862016-05-25T03:33:45ZVibration and nonlinear dynamic response of imperfect three-phase polymer nanocomposite panel resting on elastic foundations under hydrodynamic loadsDinh Duc Nguyenducnd@vnu.edu.vnHadavinia HomayounVan Thu PhamQuoc Quan Tran2016-05-25T03:30:06Z2016-05-25T03:30:43Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1684This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16842016-05-25T03:30:06ZNonlinear response of shear deformable S-FGM shallow spherical shell with ceramic-metal-ceramic layers resting on elastic foundation in thermal environmentThi Thuy Anh VuDinh Duc Nguyenducnd@vnu.edu.vn2016-05-25T03:23:54Z2016-05-25T03:29:42Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1679This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16792016-05-25T03:23:54ZNonlinear stability of shear deformable eccentrically stiffened functionally graded plates on elastic foundations with temperature-dependent propertiesHong Cong PhamThi Ngoc An PhamDinh Duc Nguyenducnd@vnu.edu.vn2016-05-25T03:02:11Z2016-05-25T03:02:11Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1674This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16742016-05-25T03:02:11ZStudy of the climate change impacts on water quality in upstream portion of the Cau River Basin, VietnamNgoc Hien HaHuy Hoang BuiThi Huong TranThanh Than TranThi Thu Ha PhamDang Toan TaMinh Son Nguyen2016-05-25T03:01:12Z2016-05-25T03:01:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1673This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16732016-05-25T03:01:12ZTuning of PID Controllers for Overhead Cranes Using Genetic AlgorithmQuang Hoang NguyenVan Khoa VuVan Diep Do2016-05-23T02:14:32Z2016-05-23T02:15:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1566This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15662016-05-23T02:14:32ZNonlinear dynamic and stability analysis of ES-FGM plates on elastic foundationSince its first introduction in 1984 by a group of material scientists in Japan, functionally graded materials (FGMs) have attracted considerable attention in many engineering applications namely extremely high temperature resistant materials. Eccentrically stiffened FGM (ES-FGM) was firstly studied in 2011 [1]. After that, ES-FGM was attracted and studied more by many authors; however, their studies mainly used classical theory and did not study the effects of temperature on stiffeners. This paper presents an analytical approach to investigate the nonlinear dynamic response and stability analysis of centrically stiffened FGM plates on elastic foundation using both of the first order shear deformation plate theory and stress function. The ES-FGM plates are assumed to rest on elastic foundation and subjected to mechanical, thermal loads in thermal environment.Hong Cong PhamDinh Duc Nguyenducnd@vnu.edu.vn2016-05-23T02:13:18Z2016-05-23T02:14:05Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1567This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15672016-05-23T02:13:18ZOn the nonlinear stability of eccentrically stiffened functionally graded annular spherical segmentThe nonlinear stability of eccentrically stiffened functionally graded (FGM) annular spherical segment resting on elastic foundations under external pressure is studied analytically. The FGM annular spherical segments are reinforced by eccentrically longitudinal and transversal stiffeners made of full metal or ceramic depending on situation of stiffeners at metal-rich or ceramic-rich side of the shell respectively. Based on the classical thin shell theory, the governing equations of FGM annular spherical segments are derived. Approximate solutions are assumed to satisfy the simply supported boundary condition of segments and Galerkin method is applied to study the stability. Numerical results are given to evaluate effects of homogeneous, dimensional parameters, outside stiffeners, elastic foundations to the stability of the structures.Thi Thuy Anh Vuvuanhthuy206@gmail.comDinh Duc Nguyenducnd@vnu.edu.vn2016-05-20T09:04:35Z2016-05-20T09:05:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1509This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15092016-05-20T09:04:35ZPhân tích ổn định cơ và nhiệt của panel nón FGM có gân gia cường trên nền đàn hồi trong môi trường nhiệtMinh Anh Vuvuminhanhhp@gmail.comDinh Quang Vuquangvd2510@gmail.comDinh Duc Nguyenducnd@vnu.edu.vn2016-05-20T09:03:07Z2016-05-20T09:04:21Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1508This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15082016-05-20T09:03:07ZPhân tích ổn định phi tuyến của panel trụ làm bằng vật liệu composite FGM có gân gia cường trên nền đàn hồi chịu tải cơ, nhiệt và cơ – nhiệt kết hợpVan Anh Trananhtv0511@gmail.comVan Quyen Nguyenvanquyen.uet@gmail.comDinh Duc Nguyenducnd@vnu.edu.vn2016-05-20T09:01:40Z2016-05-20T09:02:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1507This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15072016-05-20T09:01:40ZNghiên cứu, phân tích và viết chương trình phát hiện các sóng trên điện tâm đồ ứng dụng trong chẩn đoán bệnh về timNhu Chi Trantrannhuchi@gmail.comDuy BuiKhanh NguyenHong Quan DauDuc Trinh Chutrinhcd@vnu.edu.vn2016-05-20T09:00:46Z2016-05-20T09:01:32Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1506This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15062016-05-20T09:00:46ZThiết kế máy phát điện chuyển động thẳng công suất 5KWVan Tien Đoannangvang02041994@gmail.comThe Ba Dangbadt@vnu.edu.vn2016-02-16T03:27:16Z2016-02-16T03:27:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1485This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/14852016-02-16T03:27:16ZVật liệu polymer compozit sợi thủy tinhDinh Duc Nguyenducnd@vnu.edu.vn2015-12-04T04:44:18Z2015-12-04T04:45:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/855This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8552015-12-04T04:44:18ZNumerical Simulation of a Wave Energy Converter Using Linear GeneratorThe Ba Dangbadt@vnu.edu.vn2015-12-04T04:26:44Z2015-12-04T04:29:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/856This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8562015-12-04T04:26:44ZUnderstanding of Unsteady Pressure Fields on Prisms based on Covariance and Spectral Proper Orthogonal DecompositionsThis paper presents applications of proper orthogonal decomposition in both the time and frequency domains based on both cross spectral matrix and covariance matrix branches to analyze multi-variate unsteady pressure fields on prisms and to study spanwise and chordwise pressure distribution. Furthermore, modification of proper orthogonal decomposition is applied to a rectangular spanwise coherence matrix in order to investigate the spanwise correlation and coherence of the unsteady pressure fields. The unsteady pressure fields have been directly measured in wind tunnel tests on some typical prisms with slenderness ratios B/D=1, B/D=1 with a splitter plate in the wake, and B/D=5. Significance and contribution of the first covariance mode associated with the first principal coordinates as well as those of the first spectral eigenvalue and associated spectral mode are clarified by synthesis of the unsteady pressure fields and identification of intrinsic events inside the unsteady pressure fields. Spanwise coherence of the unsteady pressure fields has been mapped the first time ever for better understanding of their intrinsic characteristics.Thai Hoa LeYukio TamuraMasaru MatsumotoHiromichi Shirato2015-12-04T04:03:13Z2015-12-04T04:18:07Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/858This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8582015-12-04T04:03:13ZWavelet Conherence of Pressure on Rectangular CylindersThai Hoa Lethle@vnu.edu.vn2015-12-04T04:01:09Z2015-12-04T04:01:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/859This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8592015-12-04T04:01:09ZSpatial corelation of pressure fields on retangular cylinders under turbulent flowsLe Thai HoaTruong Viet Hung2015-12-04T03:53:17Z2015-12-04T03:56:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/860This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8602015-12-04T03:53:17ZStuding the Effect of Rainwater Rivulets on a cable Subjected to WindsThai Hoa Lethle@vnu.edu.vnViet Hung Truong2015-11-26T06:05:39Z2015-11-26T06:06:36Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1218This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12182015-11-26T06:05:39ZNonlinear Response of Imperfect Eccentrically Stiffened Ceramic-Metal-Ceramic FGM Circular Cylindrical Shells Surrounded on Elastic Foundations and Subjected to Axial CompressionDinh Duc Nguyenducnd@vnu.edu.vnToan Thang Pham2015-11-26T06:03:07Z2015-11-26T06:05:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1219This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12192015-11-26T06:03:07ZNonlinear Response of Shear Deformable FGM Curved Panels Resting on Elastic Foundations and Subjected to Mechanical and Thermal Loading ConditionsThis paper presents an analytical investigation on the nonlinear response of thick functionally graded doubly curved shallow panels resting on elastic foundations and subjected to some conditions of mechanical, thermal, and thermomechanical loads. Material properties are assumed to be temperature independent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of constituents. The formulations are based on higher order shear deformation shell theory taking into account geometrical nonlinearity, initial geometrical imperfection and Pasternak type elastic foundation. By applying Galerkin method, explicit relations of load-deflection curves for simply supported curved panels are determined. Effects of material and geometrical properties, in-plane boundary restraint, foundation stiffness and imperfection on the buckling and postbuckling loading capacity of the panels are analyzed and discussed. The novelty of this study results from accounting for higher order transverse shear deformation and panel-foundation interaction in analyzing nonlinear stability of thick functionally graded cylindrical and spherical panels.Van Tung HoangDinh Duc Nguyenducnd@vnu.edu.vn2015-11-26T06:00:13Z2015-11-26T06:02:37Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1220This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12202015-11-26T06:00:13ZNonlinear Vibration of Imperfect Eccentrically Stiffened Functionally Graded Double Curved Shallow Shells Resting on Elastic Foundation using the First Order Shear Deformation TheoryThis paper presents an analytical approach to investigate the nonlinear dynamic response and vibration of imperfect eccentrically stiffened FGM thick double curved shallow shells on elastic foundation using both the first order shear deformation theory and stress function with full motion equations (not using Volmir's assumptions). The FGM shells are assumed to rest on elastic foundation and subjected to mechanical and damping loads. Numerical results for dynamic response of the FGM shells are obtained by Runge–Kutta method. The results show the influences of geometrical parameters, the material properties, imperfections, the elastic foundations, eccentrically stiffeners and mechanical loads on the nonlinear dynamic response and nonlinear vibration of functionally graded double curved shallow shells. The numerical results in this paper are compared with results reported in other publications.Huy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan Tran2015-11-26T05:56:36Z2015-11-26T05:57:50Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1224This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12242015-11-26T05:56:36ZNonlinear Analysis on Flutter of Sigmoid-Functionally Graded Material Plates with Ceramic-Metal-Ceramic Layers on Elastic FoundationHong Cong PhamHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2015-11-26T05:54:38Z2015-11-26T05:56:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1225This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12252015-11-26T05:54:38ZNonlinear Analysis on Flutter of Sigmoid-Functionally Graded Cylindrical Panels on Elastic Foundations using Ilyshin Supersonic Aerodynamic TheoryQuoc Quan TranHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2015-11-26T05:52:30Z2015-11-26T05:53:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1226This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12262015-11-26T05:52:30ZNonlinear Post-Buckling Analysis of Thin Sigmoid FGM Annular Spherical Shells Surrounded on Elastic Foundations under Uniform External Pressure Including Temperature EffectsThi Thuy Anh VuHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2015-11-26T05:51:01Z2015-11-26T05:52:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1227This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12272015-11-26T05:51:01ZNonlinear Vibration of Thick Sigmoid-FGM Plates on Elastic Foundation Subjected to Thermal Load using the Third Order Shear Deformation TheoryDinh Duc Nguyenducnd@vnu.edu.vnHong Cong PhamJung Il Song2015-11-24T07:52:50Z2015-11-24T07:54:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1214This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12142015-11-24T07:52:50ZNonlinear Response of Imperfect Eccentrically Stiffened Ceramic-Metal-Ceramic S-FGM Thin Circular Cylindrical Shells Surrounded on Elastic Foundations under Uniform Radial LoadDinh Duc Nguyenducnd@vnu.edu.vnToan Thang Pham2015-11-24T07:52:35Z2015-11-24T07:52:35Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/864This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8642015-11-24T07:52:35ZPhương pháp xác định mặt phẳng nghiêng sử dụng cảm biến siêu âm trong mô hình rửa xe tự độngĐinh Trần Hiệphiep.tran.dinh@vnu.edu.vnPhạm Mạnh Thắngthangpm@vnu.edu.vnHoàng Văn MạnhNguyễn Văn QuyềnTrịnh Quốc Trung2015-11-24T07:49:52Z2015-11-24T07:52:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1223This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12232015-11-24T07:49:52ZNonlinear Postbuckling of an Eccentrically Stiffened Thin FGM Plate Resting on Elastic Foundation in Thermal EnvironmentsDinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2015-11-24T07:48:23Z2015-11-24T07:49:37Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1211This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12112015-11-24T07:48:23ZNonlinear Thermal Stability of Eccentrically Stiffened Functionally Graded Truncated Conical Shells Surrounded on Elastic FoundationsThis paper studies the thermal stability of an eccentrically stiffened functionally graded truncated conical shells in thermal environment and surrounded on elastic foundations. Both of the FGM shell as well as the stiffeners are deformed under temperature. The formulations are based on the classical shell theory taking into account geometrical nonlinearity, initial geometrical imperfection, temperature-dependent properties and the Lekhnitsky smeared stiffeners technique with Pasternak type elastic foundation. By applying Galerkin method, the closed-form expression for determining the thermal buckling load is obtained. The numerical results show that the critical thermal load in the case of the uniform temperature rise is smaller than one of the linear temperature distribution through the thickness of the shell, and the critical thermal load increases when increasing the coefficient of stiffeners and vice versa. The paper also analyzes and discussed the significant effects of material and geometrical properties, elastic foundations on the thermal buckling capacity of the eccentrically stiffened FGM truncated conical shell in thermal environment. The obtained results are validated by comparing with those in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnHong Cong Pham2015-11-24T07:45:38Z2015-11-24T07:46:49Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1212This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12122015-11-24T07:45:38ZNonlinear Stability Analysis of Thin FGM Annular Spherical Shells on Elastic Foundations under External Pressure and Thermal LoadsTo increase the thermal resistance of various structural components in high-temperature environments, the present research deals with nonlinear stability analysis of thin annular spherical shells made of functionally graded materials (FGM) on elastic foundations under external pressure and temperature. Material properties are graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of constituents. Classical thin shell theory in terms of the shell deflection and the stress function is used to determine the buckling loads and nonlinear response of the FGM annular spherical shells. Galerkin method is applied to obtain closed – form of load – deflection paths. An analysis is carried out to show the effects of material, geometrical properties, elastic foundations and combination of external pressure and temperature on the nonlinear stability of the annular spherical shells.Thi Thuy Anh Vuvuanhthuy206@gmail.comHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2015-11-24T07:44:16Z2015-11-24T07:45:24Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1217This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12172015-11-24T07:44:16ZNonlinear Response of Imperfect Eccentrically Stiffened FGM Cylindrical Panels on Elastic Foundation Subjected to Mechanical LoadsIn the present paper, the nonlinear response of eccentrically stiffened FGM cylindrical panels on elastic foundation subjected to mechanical loads is presented. Material properties are graded in the thickness direction of the FGM panel according to a simple power law distribution. By applying Bubnov-Galerkin method, the Lekhnitsky smeared stiffeners technique with Pasternak type elastic foundation and stress function, explicit relations of load-deflection curves for simply supported eccentrically stiffened FGM panels are determined. Numerical results are given for evaluate effects of material and geometrical properties, elastic foundation and eccentrically outside stiffeners on the buckling and postbuckling of the FGM panels. The obtained results are validated by comparing with those in the literature.
Nonlinear response of imperfect eccentrically stiffened FGM cylindrical panels on elastic foundation subjected to mechanical loads. Available from: http://www.researchgate.net/publication/260268771_Nonlinear_response_of_imperfect_eccentrically_stiffened_FGM_cylindrical_panels_on_elastic_foundation_subjected_to_mechanical_loads [accessed Aug 6, 2015].Dinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan Tran2015-11-24T07:42:34Z2015-11-24T07:43:51Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1215This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12152015-11-24T07:42:34ZTransient Responses of Functionally Graded Double Curved Shallow Shells with Temperature-Dependent Material Properties in Thermal EnvironmentAn analytical approach is presented to investigate the nonlinear dynamic response and vibration of imperfect eccentrically stiffened FGM double curved thin shallow shells on elastic foundation using a simple power-law distribution (P-FGM) in thermal environment. The formulations are based on the classical shell theory taking into account geometrical nonlinearity, initial geometrical imperfection, temperature-dependent properties and the Lekhnitsky smeared stiffeners technique with Pasternak type elastic foundation. By applying Galerkin method and using stress function, explicit relations of thermal load-deflection curves for simply supported curved eccentrically stiffened FGM shells are determined. Effects of material and geometrical properties, temperature, elastic foundation and eccentrically stiffeners on the dynamic response and vibration of the imperfect eccentrically stiffened P-FGM double curved shallow shells in thermal environments are analyzed and discussed. The numerical results in this paper are compared with results reported in other publications.Dinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan Tran2015-11-24T07:39:24Z2015-11-24T07:42:10Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1216This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12162015-11-24T07:39:24ZNonlinear Buckling of Imperfect Eccentrically Stiffened Metal-Ceramic-Metal S-FGM Thin Circular Cylindrical Shells with Temperature-Dependent Properties in Thermal EnvironmentsIn this paper, an analytical approach is presented to investigate the nonlinear static buckling for imperfect eccentrically stiffened functionally graded thin circular cylindrical shells with temperature-dependent properties surrounded on elastic foundation in thermal environment. Both shells and stiffeners are deformed simultaneously due to temperature. Material properties are graded in the thickness direction according to a Sigmoid power law distribution in terms of the volume fractions of constituents (S-FGM) with metal–ceramic–metal layers. The Lekhnitsky smeared stiffeners technique with Pasternak type elastic foundation, stress function and the Bubnov–Galerkin method are applied. Numerical results are given for evaluating effects of temperature, material and geometrical properties, elastic foundations and eccentrically outside stiffeners on the buckling and post-buckling of the S-FGM shells. The obtained results are validated by comparing with those in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnToan Thang Pham2015-11-24T07:37:51Z2015-11-24T07:39:00Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1222This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12222015-11-24T07:37:51ZNonlinear Stability Analysis of Imperfect Three-Phase Polymer Composite Plates in Thermal EnvironmentsThis paper presents an analytical investigation on the nonlinear response of the thin imperfect laminated three-phase polymer composite plate in thermal environments. The formulations are based on the classical plate theory taking into account the interaction between the matrix and the particles, geometrical nonlinearity, initial geometrical imperfection. By applying Galerkin method, explicit relations of load–deflection curves are determined. Obtained results show effects of the fibers and the particles, material, geometrical properties and temperature on the buckling and post-buckling loading capacity of the three phase composite plate, therefore we can proactively design materials and structural composite meet the technical requirements as desired when adjustment components.Dinh Duc Nguyenducnd@vnu.edu.vnVan Thu Pham2015-11-24T07:35:37Z2015-11-24T07:37:32Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1228This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12282015-11-24T07:35:37ZNonlinear Dynamic Analysis and Vibration of Imperfect Three Phase Polymer Nanocomposite Panel Resting on Elastic Foundation under Hydrodynamic LoadsVan Thu PhamQuoc Quan TranHadavinia HomayounDinh Duc Nguyenducnd@vnu.edu.vn2015-11-21T16:01:14Z2015-11-21T16:02:12Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1236This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12362015-11-21T16:01:14ZThe study of Fiber Bragg Gratting Sensor based on Self-mixing Interferometry for Static Strain MeasurementThanh Binh PhamThe Anh NguyenThuy Van NguyenNgoc Linh Nguyennlnguyen@vnu.edu.vnHuy BuiCheng Seat HanVan Hoi Pham2015-11-21T15:13:09Z2015-11-21T15:15:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1221This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12212015-11-21T15:13:09ZNonlinear Axisymmetric Response of FGM Shallow Spherical shells on Elastic Foundations under Uniform External Pressure and TemperatureBased on the classical shell theory taking into account geometrical nonlinearity, initial geometrical imperfection and Pasternak type elastic foundation, the nonlinear axisymmetric response of shallow spherical FGM shells under mechanical, thermal loads and different boundary conditions is considered in this paper. Using the Bubnov–Galerkin method and stress function, obtained results show effects of elastic foundations, external pressure, temperature, material and geometrical properties on the nonlinear buckling and postbuckling of the shells. The snap-through behaviors of the FGM spherical shallow shells on elastic foundations also are analyzed carefully in this paper. Some results were compared with the ones of other authors.Dinh Duc Nguyenducnd@vnu.edu.vnThi Thuy Anh VuHong Cong Pham2015-11-19T09:15:43Z2015-11-19T09:16:23Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1246This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12462015-11-19T09:15:43ZSimple Radiative Model for Modeling Coupled Heat Transfer in Semi-Transparent MaterialsHoang Quan Nguyenquannh@vnu.edu.vnVan Phu Le2015-11-19T08:51:50Z2015-11-19T09:19:04Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1247This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12472015-11-19T08:51:50ZXác định đặc trưng vỉa nứt nẻ tự nhiên bằng mô hình mạng thần kinh nhân tạo (ANN)The Ba Dangbadt@vnu.edu.vn2015-11-19T08:48:32Z2015-11-19T08:49:43Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1248This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12482015-11-19T08:48:32ZNumerical Simulation and Experimental Analysis for a Linear Trigonal Double-Face Permanent Magnet Generator used in Direct Driven Wave Energy ConversionThe Ba Dangbadt@vnu.edu.vn2015-11-19T08:47:59Z2015-11-19T09:18:18Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1249This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12492015-11-19T08:47:59ZNghiên cứu phát triển thuật toán và chương trình thô hóa các tham số thuộc tính từ lưới địa chất sang lưới mô phỏng của các vỉa dầu khíThe Ba Dangbadt@vnu.edu.vn2015-11-19T08:43:16Z2015-11-19T08:43:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1209This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12092015-11-19T08:43:16ZNonlinear buckling of higher deformable S-FGM thick circular cylindrical shells with metal-ceramic-metal layers surrounded on elastic foundations in thermal environmentAn analytical approach on the nonlinear response of thick functionally graded circular cylindrical shells with temperature independent material property surrounded on elastic foundations subjected to mechanical and thermal loads is presented. Material properties are graded in the thickness direction according to a Sigmoid power law distribution in terms of the volume fractions of constituents (S-FGM). The formulations are based on the third order shear deformation shell theory taking into account von Karman nonlinearity, initial geometrical imperfection and Pasternak type elastic foundation. By applying Galerkin method and using stress function, explicit relations of thermal load–deflection curves of the S-FGM shells are determined. Detailed parametric studies are carried out to investigate effects of volume fraction index, material properties and geometrical shapes, axial compressions and thermal load, foundation stiffness and imperfection on nonlinear buckling behaviors of S-FGM thick circular cylindrical shells. The present analysis is validated by comparing results with other publications.Dinh Duc Nguyenducnd@vnu.edu.vnToan Thang PhamTrong Dao NguyenVan Tac Hoang2015-11-19T08:41:40Z2015-11-19T08:42:27Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1250This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12502015-11-19T08:41:40ZApplication of Fuzzy Logic to Evaluate the Connectivity between Injection and Production Wells in Naturally Fractured ReservoirThe Ba Dangbadt@vnu.edu.vn2015-11-19T08:34:12Z2015-11-19T09:22:39Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1235This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12352015-11-19T08:34:12ZThe Nonlinear Post-buckling of Thin FGM Annular Spherical Shells Under Mechanical Loads and Resting on Elastic FoundationsThi Thuy Anh VuHuy Bich DaoDinh Duc Nguyenducnd@vnu.edu.vn2015-11-19T08:12:28Z2015-11-19T08:13:54Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1237This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12372015-11-19T08:12:28ZTính không ổn định của phương pháp phần tử hữu hạn trong trường hợp lưới không đềuCao Son Nguyensonnc@vnu.edu.vn2015-11-19T07:58:32Z2015-11-19T08:08:43Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1242This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12422015-11-19T07:58:32ZResponse Analysis of Van der Pol Oscillator Subjected to Harmonic and Random ExcitationsThe response of the Van der Pol oscillator subjected to combined harmonic and random excitations is investigated by a technique combining two excellent methods, namely the stochastic averaging method and the equivalent linearization method. The original equation is averaged by the stochastic averaging method at first. Then the resulting nonlinear averaged equations are linearized by the equivalent linearization method so that the equations obtained can be solved exactly by the technique of auxiliary function. The mean square response of the Van der Pol oscillator is computed algebraically and compared to the ones obtained by numerical simulation and by technique combining methods of stochastic averaging and equivalent non-linearization. The results show that the proposed technique gives a good prediction on mean square responses of the Van der Pol oscillator. In addition, the proposed technique can be applied to other nonlinear systems for it does not require any special conditions, and it can be improved by advanced optimization criteria of the equivalent linearization method.Dong Anh NguyenL. Zakovorotny V.N. Hao D.2015-11-19T07:56:42Z2015-11-19T07:57:22Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1243This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12432015-11-19T07:56:42ZDesign of non-traditional dynamic vibration absorber for damped linear structures, Proceedings of the Institution of Mechanical EngineersDong Anh NguyenN.X. Nguyen2015-11-19T07:50:46Z2015-11-19T07:51:58Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1240This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12402015-11-19T07:50:46ZExtension of the Regulated Stochastic Linearization to Beam VibrationsIn this study, a version of the regulated stochastic linearization technique is proposed for the nonlinear random vibrations of Bernoulli–Euler nonlinear beams. For analysis, in order to balance the error of linearization, we utilize the regulated technique; namely, the appearing nonlinear terms are first replaced by higher-order nonlinear expressions that are subsequently reduced, in stages, to linear ones. It is demonstrated that this seemingly a “roundabout” way is extremely effective to derive a solution that turns out to be much closer to the results provided by the Monte Carlo simulation than those derived via the conventional or potential energy linearization techniques, in the cases of large nonlinearity.Dong Anh NguyenI. ElishakoffN. Hieu Nguyen2015-11-19T07:37:01Z2015-11-19T07:38:11Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1244This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12442015-11-19T07:37:01ZGlobal-local Approach to the Design of Dynamic Vibration Absorber for Damped StructuresThe dynamic vibration absorber (DVA) has attracted attention since its invention. This paper deals with the optimization problems of the standard DVA and two other models of DVA called three-element DVA and non-traditional DVA for damped primary structures. Unlike the standard configuration, the three-element DVA contains two spring elements in which one is connected to a dashpot in a series and the other is placed in parallel. Meanwhile the non-traditional DVA has a linear viscous damper connecting the absorber mass directly to the ground. There have been some studies on the design of three-element and non-traditional dynamic vibration absorbers in the case of undamped primary structures.
These studies have shown that both three-element and non-traditional DVAs perform better than the standard DVA.
When the primary structure is damped, there are very few studies on the three-element and non-traditional DVAs in the literature. This article proposes a global-local approach to give approximate analytical solutions of the H1 optimization for all standard, three-element and non-traditional DVAs attached to damped primary structures. The main idea of the study is based on the global-local criterion of the equivalent linearization method in order to replace approximately the original damped structure by an equivalent undamped one. Afterwards, the already derived expressions of the optimal parameters for the undamped primary system case are used with the equivalent undamped structure that was just obtained. The numerical simulations are carried out to verify the effectiveness of the obtained results. Additionally, design aids, which show the variation of the optimal design quantities for various DVA mass ratios and inherent structural damping ratios are also provided.Dong Anh NguyenXuan Nguyen NguyenHoang Quan Nguyenquannh@vnu.edu.vn2015-11-08T08:51:53Z2015-11-09T05:56:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1268This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12682015-11-08T08:51:53ZThe Temperature-Sensitivity of a Critical Electric Field Induced Magnetic Easy-Axis Reorientation Ferromagnetic/Ferroelectric Layered HeterostructuresWe have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in polycrystalline ferromagnetic (FM) nano-scale thin films, i.e. (001)-oriented cubic films such as Fe, Ni, CFO and (0001)-oriented hexagonal films such as Co, grown on ferroelectric (FE) substrates, for example PZT, BTO substrates. The model of FM/FE bilayered heterostructures has been applied to study the total free energy of the FM films. By minimizing this energy, we have shown that temperature has a significant effect on a critical electric field induced magnetic reorientation.Thi Minh Hong Nguyenhongntm@vnu.edu.vnDuc Thang Phampdthang@vnu.edu.vnDinh Long Dangddlong@vnu.edu.vnThai Ha PhamNgoc Trung NguyenHong Cong PhamDinh Duc Nguyenducnd@vnu.edu.vn2015-11-03T15:10:49Z2015-11-03T15:12:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1307This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/13072015-11-03T15:10:49ZWORL: a Nonmonotonic Rule Language for the Semantic WebThanh Son CaoLinh Anh NguyenAndrzej Szalas2015-08-27T16:52:41Z2015-08-27T16:52:41Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1382This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/13822015-08-27T16:52:41ZNonlinear Dynamic Analysis and Vibration of Shear Deformable Piezoelectric FGM Double Curved Shallow Shells under Damping-Thermo-Electro-Mechanical LoadsNonlinear dynamic analysis and vibration of imperfect functionally graded materials (FGM) thick double curved shallow shells with piezoelectric actuators on elastic foundations subjected to the combination of electrical, thermal, mechanical and damping loading are investigated in this paper. Material properties of FGM shells are assumed to be temperature dependent and graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The governing equations are established based on Reddy’s higher order shear deformation theory that includes thermo-piezoelectric effects and are solved by the stress function, the Galerkin method and fourth-order Runge–Kutta method. In numerical results, the effects of geometrical parameters; the material properties; imperfections; elastic foundations; electrical, mechanical, thermal and damping loads on the nonlinear dynamic analysis and nonlinear vibration of the FGM hybrid double curved shallow shells are discussed.Dinh Duc Nguyenducnd@vnu.edu.vnQuoc Quan TranDinh Luat Vu2015-08-14T07:46:02Z2015-08-14T07:46:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1234This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12342015-08-14T07:46:02ZNonlinear Post-Buckling of Thin FGM Annular Spherical Shells Under Mechanical Loads and Resting on Elastic FoundationsDinh Duc Nguyenducnd@vnu.edu.vnThi Thuy Anh VuHuy Bich Dao2015-08-14T06:59:43Z2015-08-14T07:53:59Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1233This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12332015-08-14T06:59:43ZNonlinear Dynamic and Vibration of Imperfect Sigmoid-Functionally Graded Double Curved Shallow Shells Resting on Elastic Foundations using the First Order Shear Deformation TheoryQuoc Quan TranHui - Shen ShenDinh Duc Nguyenducnd@vnu.edu.vn2015-08-14T06:55:51Z2015-08-14T07:55:39Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1231This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12312015-08-14T06:55:51ZNonlinear Response of Axisymmetric Shear Deformable Sigmoid FGM Shallow Spherical Shells Resting on Elastic Foundations under External PressureVan Dung VuThi Thuy Anh VuDinh Duc Nguyenducnd@vnu.edu.vn2015-08-14T06:53:11Z2015-08-14T07:51:56Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1230This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/12302015-08-14T06:53:11ZNonlinear Analysis on Flutter of S-FGM Thin Circular Cylindrical Shells with Metal-Ceramic-Metal Layers Surrounded on Elastic Foundations using Ilyushin Supersonic Aerodynamic TheoryDinh Duc Nguyenducnd@vnu.edu.vnB.E. PobedryaHuy Bich DaoToan Thang Pham2015-04-20T07:58:31Z2015-04-20T07:58:31Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/862This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/8622015-04-20T07:58:31ZLow-Power Wireless Security System in the Home AutomationManh Thang Phamthangpm@vnu.edu.vn2013-08-08T06:25:08Z2013-08-08T06:25:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/177This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1772013-08-08T06:25:08ZPhương pháp xác định mặt phẳng nghiêng sử dụng cảm biến siêu âm trong mô hình rửa xe tự độngTran Hiep Dinhtranhiep.dinh@vnu.edu.vnManh Thang Pham thangpm@vnu.edu.vnVan Manh HoangVan Quyen Nguyen Quoc Trung Trinh2013-08-08T03:42:19Z2013-08-08T03:42:19Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/173This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1732013-08-08T03:42:19ZStudying the Effect of Rainwater Rivulets on a Cable Subjected to WindsThai Hoa Lethle@vnu.edu.vnViet Hung Truong2013-08-08T03:30:30Z2013-08-08T03:30:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/172This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1722013-08-08T03:30:30ZSpatial Correlation of Pressure Fields on Rectangular Cylinders Under Turbulent FlowsThai Hoa Lethle@vnu.edu.vnViet Hung Truong 2013-08-08T03:08:26Z2013-08-08T03:08:26Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/171This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1712013-08-08T03:08:26ZWavelet Coherence of Pressure on Rectangular CylindersThai Hoa Lethle@vnu.edu.vn2013-08-08T03:00:40Z2013-08-08T03:00:40Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/176This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1762013-08-08T03:00:40ZLow-Power Wireless Security System in the Home AutomationManh Thang Pham thangpm@vnu.edu.vn2013-08-08T02:59:38Z2013-08-08T02:59:38Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/174This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1742013-08-08T02:59:38ZHigh Security RF Remote ControllerManh Thang Pham thangpm@vnu.edu.vnVan Quyen Nguyen 2013-07-17T04:24:34Z2013-07-17T04:24:34Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/165This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1652013-07-17T04:24:34ZNonlinear Postbuckling of Symmetric S-FGM Plates Resting on Elastic Foundations using Higher Order Shear Deformation Plate Theory in Thermal Environments This paper presents an analytical investigation on the postbuckling behaviors of thick symmetric functionally graded plates resting on elastic foundations and subjected to thermomechanical loads in thermal environments. Material properties are graded in the thickness direction according to a Sigmoi power law distribution in terms of the volume fractions of constituents (S-FGM). The formulations are based on third order shear deformation plate theory and stress function taking into account Von Karman nonlinearity, initial geometrical imperfection, temperature and Pasternak type elastic foundation. By applying Galerkin method, closed-form relations of buckling loads and postbuckling equilibrium paths for simply supported plates are determined. The effects of material and geometrical properties, temperature, boundary conditions, foundation stiffness and imperfection on the mechanical and thermal buckling and postbuckling loading capacity of the S-FGM plates are analyzed and discussed. Nguyen Dinh Ducducnd@vnu.edu.vnPham Hong Cong2013-07-17T04:23:29Z2013-07-17T04:23:29Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/166This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1662013-07-17T04:23:29ZCorrigendum to Nonlinear Dynamic Response of Imperfect Eccentrically Stiffened (FGM) Double Curved Shallow Shells on Elastic Foundation ComposThis paper presents an analytical investigation on the postbuckling behaviors of thick symmetric functionally graded plates resting on elastic foundations and subjected to thermomechanical loads in thermal environments. Material properties are graded in the thickness direction according to a Sigmoi power law distribution in terms of the volume fractions of constituents (S-FGM). The formulations are based on third order shear deformation plate theory and stress function taking into account Von Karman nonlinearity, initial geometrical imperfection, temperature and Pasternak type elastic foundation. By applying Galerkin method, closed-form relations of buckling loads and postbuckling equilibrium paths for simply supported plates are determined. The effects of material and geometrical properties, temperature, boundary conditions, foundation stiffness and imperfection on the mechanical and thermal buckling and postbuckling loading capacity of the S-FGM plates are analyzed and discussedNguyen Dinh Duc2013-07-17T04:21:48Z2013-07-17T04:22:03Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/164This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1642013-07-17T04:21:48ZNumerical Simulation of a Wave Energy Converter Using Linear GeneratorThe Ba Dangbadt@vnu.edu.vn2013-06-29T03:13:02Z2013-08-08T03:39:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/161This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1612013-06-29T03:13:02ZDesign of Three-Element Dynamic Vibration Absorber for Damped Linear StructuresD.A. NguyenN.X. NguyenThai Hoa Lethle@vnu.edu.vn2013-06-29T03:04:57Z2013-08-08T03:22:04Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/160This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1602013-06-29T03:04:57ZUnderstanding of Unsteady Pressure Fields on Prism based on Covariance and Spectral Proper Orthogonal DecompositionsThai Hoa Lethle@vnu.edu.vnY. TamuraM. MatsumotoH. Shirato2013-01-03T06:04:16Z2013-01-03T06:04:16Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/110This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1102013-01-03T06:04:16ZDetermining the Deflection of a Thin Composite Plate in an Unsteady Temperature FieldThe buckling behavior of a thin particle-reinforced composite plate under the influence of an unsteady temperature field and a temperature gradient across its thickness is investigated. An analytic solution for bending of the plate is obtained in the form of double trigonometric series. Based on the analytic result, a numerical test is carried out to study the thickness and time dependences of the buckling behavior of a plate made of a PVC matrix and titanium particles.Dinh Duc Nguyenducnd@vnu.edu.vnThi Thu Hu Nghiem2013-01-03T06:00:20Z2013-01-03T06:00:20Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/109This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1092013-01-03T06:00:20ZNonlinear Stability Analysis of Double-Curved Shallow FGM Panels on Elastic Foundations in Thermal EnvironmentsAn analytical investigation into the nonlinear response of thick functionally graded double-curved shallow panels resting on elastic foundations and subjected to thermal and thermomechanical loads is presented. Young’s modulus and Poisson’s ratio are both graded in the thickness direction according to a simple power-law distribution in terms of volume fractions of constituents. All formulations are based on the classical shell theory with account of geometrical nonlinearity and initial geometrical imperfection in the cases of Pasternak-type elastic foundations. By applying the Galerkin method, explicit relations for the thermal load–deflection curves of simply supported curved panels are found. The effects of material and geometrical properties and foundation stiffness on the buckling and postbuckling load-carrying capacity of the panels in thermal environments are analyzed and discussed.Dinh Duc Nguyenducnd@vnu.edu.vnTranQuoc Quan