Degradation of thermal postbuckling behaviors of functionally graded material in aero-hygrothermal environments

2014 ◽  
Vol 118 ◽  
pp. 228-233 ◽  
Author(s):  
Chang-Yull Lee ◽  
Ji-Hwan Kim
2012 ◽  
Vol 535-537 ◽  
pp. 1382-1385
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim

The postbucking behaviors of Functionally Graded Material (FGM) plate in hygrothermal environments are investigated. The material properties of FGM change continuously in the thickness direction according to the volume fractions of the materials. The formulations are based on the First-order Shear Deformation Theory (FSDT) and von Karman strain-displacement relations are applied. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. Newton-Raphson technique is adopted to analyze the thermal postbuckling behavior of the model. Furthermore, moisture effects on the model are significantly appeared due to the increase of the volume fraction index of the materials.


2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Y. Kiani ◽  
M. R. Eslami

Thermal postbuckling of solid circular plates made of a through-the-thickness functionally graded material (FGM) is analyzed in this paper. Initial imperfection of the plate is also taken into account. Each thermomechanical property of the plate is assumed to be a function of the temperature and thickness coordinate. Equivalent properties of the FGM media are obtained based on three different homogenization schemes, namely, Voigt rule, Mori–Tanaka scheme, and self-consistent estimate. Temperature profile is assumed to be through-the-thickness direction only. The solution of the heat conduction equation is obtained using an iterative central finite difference scheme. Various types of thermal loadings, such as uniform temperature rise, temperature specified at surfaces, and heat flux, are considered. Nonlinear equilibrium equations of the plate are obtained by means of the conventional Ritz method. Solution of the resulting nonlinear equilibrium equations and temperature distribution are obtained simultaneously at each step of heating. It is shown that response of a perfect clamped FGM plate is of the bifurcation type of buckling with stable postbuckling equilibrium branch, whereas imperfect clamped and perfect/imperfect simply supported FGM plates do not reveal the bifurcation type of instability through the nonuniform heating process. Furthermore, amplitude of initial imperfection is an important factor on the equilibrium path of FGM circular plates, especially for simply supported ones.


2016 ◽  
Vol 58 (3) ◽  
pp. 260-268 ◽  
Author(s):  
Hassan S. Hedia ◽  
Saad M. Aldousari ◽  
Noha Fouda

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