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©2012 Civil-Comp Ltd |
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H.R. Ovesy1, S.A.M. Ghannadpour2 and M. Nassirnia1
1Department of Aerospace Engineering and Centre of Excellence in Computational Aerospace Engineering, Amirkabir University of Technology, Tehran, Iran
2Aerospace Engineering Department, Faculty of New Technologies and Engineering, Shahid Beheshti University G.C., Tehran, Iran
Keywords: postbuckling, thermal loading, classical plate theory, finite strip method, functionally graded material.
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A description is given of the semi-analytical finite strip method applied for analysing the postbuckling behaviour of functionally graded rectangular plates under thermal loadings, i.e. uniform temperature rise, and nonlinear temperature change across the thickness. The authors have developed the semi-analytical finite strip method (S-a FSM) for analysing the buckling behaviour of rectangular FGM plates under thermal loadings by incorporating the total potential energy minimization and solving the corresponding eigenvalue problem [1].
In the current research, the material properties of these plates are assumed to vary continuously through the thickness of the plate, according to the power product form of thickness coordinate variable z. The formulations are based on the classical plate theory and the concept of the principle of the minimum potential energy. The Newton-Raphson method is used to solve the non-linear equilibrium equations. According to the results of uniform temperature rise loading, the deflections related to aluminum and alumina (fully isotropic and homogenous) plates reveal clear bifurcation points while other deflections, which are functionally graded through the thickness, deform with any change in temperature.
In the nonlinear temperature change loading, two different approaches are used to solve steady state heat conduction differential equation, i.e. approximate and exact solutions. In the approximate approach, the differential equation is solved by means of a polynomial series and the approximate temperature distribution across the thickness is selected by taking the first seven terms of the series [1]. In the exact approach, the same equation is solved analytically. In this loading case, the maximum plate deflection based on the exact temperature distribution is lower than those obtained based on the approximate distribution. In addition, as volume fraction index is increased, the contained quantity of ceramic decreases. In other words, when the volume fraction index n is increased, the central displacement is increased. Moreover, the deflection of the plate subject to a uniform temperature rise is greater than that obtained for a nonlinear temperature distribution.
It can be concluded that functionally graded plates under either uniform or nonlinear temperature changes across the thickness show better postbuckling characteristics than homogenous metal plates. In other words, maximum out-of-plane deflection within the postbuckling regime is lower than those values corresponding to metal plates.
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- S.A.M. Ghannadpour, H.R. Ovesy, M. Nassirnia, "Buckling analysis of functionally graded plates under thermal loadings using the finite strip method", Computers and Structures, 2012. doi:10.1016/j.compstruc.2012.02.011
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