VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2023-05-28T13:27:27ZEPrintshttp://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/2018-12-14T01:33:30Z2018-12-18T08:22:32Zhttp://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 Nguyen2018-10-09T09:55:24Z2018-10-09T09:55:24Zhttp://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.vn2018-10-09T08:54:17Z2018-10-09T08:54:17Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/3070This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/30702018-10-09T08:54:17ZNonlinear 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 Phamnguyenpd@vnu.edu.vnDinh Khoa Nguyen2018-01-18T02:23:59Z2018-01-18T02:23:59Zhttp://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.vn2018-01-18T02:20:04Z2018-01-18T02:20:04Zhttp://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.vn2017-12-25T04:01:08Z2017-12-25T04:01:08Zhttp://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.com2017-07-24T04:00:09Z2017-07-24T04:00:09Zhttp://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.vn2017-02-06T15:50:58Z2017-02-06T15:50:58Zhttp://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.vn