scholarly journals Thermomechanical postbuckling of thick FGM plates resting on elastic foundations with tangential edge constraints

2016 ◽  
Vol 38 (1) ◽  
pp. 63-79
Author(s):  
Hoang Van Tung

This paper investigates the effects of tangential edge  constraints and elastic foundations on the buckling and postbuckling  behavior of thick FGM rectangular plates resting on elastic foundations and  subjected to thermal and thermomechanical loading conditions. 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 constituents. Governing equations are based on the higher order shear deformation plate theory incorporating the von Karman  geometrical nonlinearity, initial geometrical imperfection, tangential edge  constraints and Pasternak type elastic foundations. Approximate solutions  are assumed to satisfy simply supported boundary conditions and Galerkin  procedure is applied to derive expressions of buckling loads and  load-deflection relations. In thermal postbuckling analysis, an iteration  algorithm is employed to determine critical buckling temperatures and  postbuckling temperature-deflection equilibrium paths. The separate and  simultaneous effects of tangential edge restraints, elastic foundations and  temperature dependence of material properties on the buckling and  postbuckling responses of higher order shear deformable FGM plates are  analyzed and discussed.

2016 ◽  
Vol 38 (2) ◽  
pp. 123-140
Author(s):  
Hoang Van Tung

This paper investigates postbuckling behavior of thick  FGM cylindrical panels resting on elastic foundations and subjected to  thermal, mechanical and thermomechanical loading conditions. 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 constituents. Governing equations are based on  higher order shear deformation shell theory incorporating von Karman-Donnell  geometrical nonlinearity, initial geometrical imperfection, tangential edge  constraints and Pasternak type elastic foundations. Approximate solutions  are assumed to satisfy simply supported boundary conditions and Galerkin  procedure is applied to derive expressions of buckling loads and  load-deflection relations. In thermal postbuckling analysis, an iteration  algorithm is employed to determine critical buckling temperatures and  postbuckling temperature-deflection equilibrium paths. The separate and  simultaneous effects of tangential edge restraints, elastic foundations and  temperature dependence of material properties on the buckling and  postbuckling responses of higher order shear deformable FGM cylindrical  panels are analyzed and discussed.


2015 ◽  
Vol 07 (06) ◽  
pp. 1550082 ◽  
Author(s):  
Mohammed Sobhy

This paper deals with thermomechanical bending of functionally graded material (FGM) plates under various boundary conditions and resting on two-layer elastic foundations. One of these layers is Winkler springs with a variable modulus while the other is considered as a shear layer with a constant modulus. The plates are considered of the type having two opposite sides simply-supported, and the two other sides having combinations of simply-supported, clamped, and free boundary conditions. The temperature is obtained by solving the one-dimensional equation of heat conduction. The material properties of the plate are assumed to be graded continuously across the panel thickness. A simple power-law distribution in terms of the volume fractions of the constituents is used for estimating the effective material properties such as temperature-dependent thermoelastic properties. The governing equations are derived based on the sinusoidal shear deformation plate theory including the external load and thermal effects. The results of this theory are compared with those of other shear deformation theories. Various numerical results including the effect of boundary conditions, power-law index, plate aspect ratio, temperature difference, elastic foundation parameters, and side-to-thickness ratio on the bending of FGM plates are presented.


2011 ◽  
Vol 471-472 ◽  
pp. 709-714 ◽  
Author(s):  
Mohammad Homayoun Sadr-Lahidjani ◽  
Mohammad Hajikazemi ◽  
Mona Ramezani-Oliaee

Large deflection analysis of thin and relatively thick rectangular functionally graded plates is studied in this paper. It is assumed that the mechanical properties of the plate, graded through the thickness, are described by a simple power law distribution in terms of the volume fractions of constituents. The plate is assumed to be under lateral pressure load. The fundamental equations for rectangular plates of FGM are obtained using the classical laminated plate theory (CLPT), first order shear deformation theory (FSDT) and higher order shear deformation theory (HSDT) for large deflection and the solution is obtained by minimization of the total potential energy.


Author(s):  
Khuc Van Phu ◽  
Le Xuan Doan ◽  
Nguyen Van Thanh

 In this paper, the governing equations of rectangular plates with variable thickness subjected to mechanical load are established by using the classical plate theory, the geometrical nonlinearity in von Karman-Donnell sense. Solutions of the problem are derived according to Galerkin method. Nonlinear dynamic responses, critical dynamic loads are obtained by using Runge-Kutta method and the Budiansky–Roth criterion. Effect of volume-fraction index k and some geometric factors are considered and presented in numerical results.


2017 ◽  
Vol 39 (4) ◽  
pp. 351-364
Author(s):  
Nguyen Minh Khoa ◽  
Hoang Van Tung

This paper presents an analytical approach to investigate the nonlinear axisymmetric response of moderately thick FGM sandwich shallow spherical shells resting on elastic foundations, exposed to thermal environments and subjected to uniform external pressure. Material properties are assumed to be temperature independent, and effective properties of FGM layer are graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Formulations are based on first-order shear deformation shell theory taking geometrical nonlinearity, initial geometrical imperfection, Pasternak type elastic foundations and various degree of tangential constraint of boundary edge into consideration. Approximate solutions are assumed to satisfy clamped boundary condition and Galerkin method is applied to derive closed-form expressions of critical buckling loads and nonlinear load-deflection relation. Effects of geometrical parameters, thickness of face sheets, foundation stiffness, imperfection, thermal environments and degree of tangential edge constraints on the nonlinear stability of FGM sandwich shallow spherical shells are analyzed and discussed. 


2009 ◽  
Vol 631-632 ◽  
pp. 41-46
Author(s):  
Sun Bae Kim ◽  
Ji Hwan Kim

In this work, hypersonic aero-thermo post-buckling and thermal flutter behaviors of Functionally Graded (FG) panels under thermal and aerodynamic loads are investigated. The volume fractions of constitutive materials of the panels are gradually varied from ceramic to metal in the thickness direction based on a simple power law distribution. Thus, the material properties of the panel are also changed by a linear rule of mixture. Furthermore, the material properties are assumed to be temperature dependent because the panels are mainly used in the high temperature environments. Using the principle of virtual work, the equations of motion of the first-order shear deformation plate theory (FSDPT) are derived and the finite element method is applied to get the solution. In the formulation, the von Karman strain-displacement relationship is used for structural nonlinearity, and the partial second-order piston theory is adopted to consider the aerodynamic nonlinearity. Newton-Raphson iterative technique is used to solve the governing equations, and linear eigenvalue analysis is performed to obtain the hypersonic flutter boundaries.


2016 ◽  
Vol 20 (2) ◽  
pp. 191-218 ◽  
Author(s):  
Nguyen Dinh Duc ◽  
Pham Hong Cong

Used the Reddy's higher-order shear deformation plate theory, the nonlinear dynamic analysis and vibration of imperfect functionally graded sandwich plates in thermal environment with piezoelectric actuators (PFGM) on elastic foundations subjected to a combination of electrical, damping loadings and temperature are investigated in this article. One of the salient features of this work is the consideration of temperature on the piezoelectric layer, and the material properties of the PFGM sandwich plates are assumed to be temperature-dependent. The governing equations are established based on the stress function, the Galerkin method, and the Runge–Kutta method. In the numerical results, the effects of geometrical parameters; material properties; imperfections; elastic foundations; electrical, thermal, and damping loads on the vibration and nonlinear dynamic response of the PFGM sandwich plates are discussed. The obtained natural frequencies are verified with the known results in the literature.


2013 ◽  
Vol 13 (06) ◽  
pp. 1350033 ◽  
Author(s):  
M. H. SHERAFAT ◽  
H. R. OVESY ◽  
S. A. M. GHANNADPOUR

This paper is concerned with buckling analyses of rectangular functionally graded plates (FGPs) under uniaxial compression, biaxial compression and combined compression and tension loads. It is assumed that the plate is a mixture of metal and ceramic that its properties changes as afunction according to the simple power law distribution through the plate thickness. The fundamental eigen-buckling equations for rectangular plates of functionally graded material (FGM) are obtained by discretizing the plate into some finite strips, which are developed on the basis of the higher order plate theory (HOPT). The solution is obtained by the minimization of the total potential energy. Numerical results fora variety of FGPs are given, and compared with the available results, wherever possible. The effects of thickness ratio, variation of the volume fraction of the ceramic phase through the thickness, aspect ratio, boundary conditions and also load distribution on the buckling load capacity of FGM plates are determined and discussed. It is found that the buckling behavior of FGM plates is particularly influenced by application of HOPT, especially when the plates are thick.


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