Size-dependent thermoelastic analysis of a functionally graded nanoshell

2018 ◽  
Vol 32 (03) ◽  
pp. 1850033 ◽  
Author(s):  
Mohammad Arefi ◽  
Ashraf M. Zenkour

In this paper, two-dimensional thermoelastic analysis of a functionally graded nanoshell is presented based on nonlocal elasticity theory. To formulate this problem, first-order shear deformation theory (FSDT) is used for axial and radial deformations simultaneously. Material properties are assumed to be mixture of ceramic and metal based on a power law distribution. Principle of virtual work is used for derivation of the governing equations. The analytical approach is presented based on eigenvalue and eigenvector method to derive four unknown functions including radial and axial displacements and rotations along the longitudinal direction. In addition, the influence of nonlocal and in-homogeneous index parameter is studied on the responses of the system. Two-dimensional results are presented along the radial and longitudinal directions.

2008 ◽  
Vol 47-50 ◽  
pp. 387-390
Author(s):  
Sun Bae Kim ◽  
Ji Hwan Kim

In this study, thermal post-buckling characteristics of functionally graded (FG) panels in hypersonic airflows are investigated. The volume fraction and the material properties of FGMs are continuously changed from ceramic to metal in the thickness direction agreeably to a simple power law distribution and a linear rule of mixture, respectively. Using the principle of virtual work, the governing equations are derived and the finite element method is applied to obtain the solutions. Based on the first-order shear deformation theory (FSDT), the FG panels are modeled by the von Karman strain-displacement relation for the structural non-linearity. Also, the third-order piston theory is employed to consider the aerodynamic non-linearity.


2010 ◽  
Vol 123-125 ◽  
pp. 280-283
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim

The post-buckling of the functionally graded composite plate under thermal environment with aerodynamic loading is studied. The structural model has three layers with ceramic, FGM and metal, respectively. The outer layers of the sandwich plate are different homogeneous and isotropic material properties for ceramic and metal. Whereas the core is FGM layer, material properties vary continuously from one interface to the other in the thickness direction according to a simple power law distribution in terms of the volume fractions. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. The first-order shear deformation theory and von-Karman strain-displacement relations are based to derive governing equations of the plate. Aerodynamic effects are dealt by adopting nonlinear third-order piston theory for structural and aerodynamic nonlinearity. The Newton-Raphson iterative method applied for solving the nonlinear equations of the thermal post-buckling analysis


Author(s):  
Pham Hoang Anh ◽  
Tran Thuy Duong

In this article, an efficient numerical approach for weight optimisation of functionally graded (FG) beams in the presence of frequency constraints is presented. For the analysis purpose, a finite element (FE) solution based on the first order shear deformation theory (FSDT) is established to analyse the free vibration behaviour of FG beams. A four-parameter power law distribution and a five-parameter trigonometric distribution are used to describe the volume fraction of material constituents in the thickness direction. The goal is to tailor the thickness and material distribution for minimising the weight of FG beams while constraining the fundamental frequency to be greater than a prescribed value. The constrained optimisation problem is effectively solved by a novel differential evolution (DE) algorithm. The validity and efficiency of the proposed approach is demonstrated through two numerical examples corresponding to the four-parameter distribution and the five-parameter distribution.Keywords: FGM beam; lightweight design; frequency constraint; differential evolution.


2010 ◽  
Vol 19 (2) ◽  
pp. 096369351001900 ◽  
Author(s):  
F. Ebrahimi ◽  
H.A. Sepiani

In this study, a formulation for the free vibration and buckling of cylindrical shells made of functionally graded material (FGM) subjected to combined static and periodic axial loadings are presented. The properties are temperature dependent and graded in the thickness direction according to a volume fraction power law distribution. The analysis is based on two different methods of first-order shear deformation theory (FSDT) considering the transverse shear strains and the rotary inertias and the classical shell theory (CST). The results obtained show that the effect of transverse shear and rotary inertias on vibration and buckling of functionally graded cylindrical shells is dependent on the material composition, the temperature environment, the amplitude of static load, the deformation mode, and the shell geometry parameters.


2014 ◽  
Vol 11 (06) ◽  
pp. 1350098 ◽  
Author(s):  
ABDERRAHMANE SAID ◽  
MOHAMMED AMEUR ◽  
ABDELMOUMEN ANIS BOUSAHLA ◽  
ABDELOUAHED TOUNSI

An improved simple hyperbolic shear deformation theory involving only four unknown functions, as against five functions in case of first or other higher-order shear deformation theories, is introduced for the analysis of functionally graded plates resting on a Winkler–Pasternak elastic foundation. The governing equations are derived by employing the principle of virtual work and the physical neutral surface concept. The accuracy of the present analysis is demonstrated by comparing some of the present results with those of the classical, the first-order and the other higher-order theories.


Author(s):  
Vishesh Ranjan Kar ◽  
Subrata Kumar Panda

Free vibration responses of functionally graded spherical shell panels are investigated in the present article. A general mathematical model is developed based on higher order shear deformation theory mid-plane kinematics. The effective material properties are graded in the thickness direction according to a power-law distribution and it varies continuously from metal (bottom surface) to ceramic (top surface). The model is discretized using a nine noded quadrilateral Lagrangian element. A convergence test has been done with different mesh refinement and compared with the available published results. In addition to that the present study includes an ANSYS model check with the developed mathematical model to show the efficacy. New results are computed for different parameters such as volume fraction, thickness ratio, curvature ratio and support conditions which indicates the effect of parametric study on non-dimensional frequency parameters.


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