Post-buckling Analysis of Functionally Graded Materials Structures with Enhanced Solid-Shell Elements

This paper presents a first-order solid-shell element for the post-buckling behavior of functionally graded material (FGM) structures based on the enhanced assumed strain (EAS) with five parameters. The EAS three-dimentional finite element formulation presented in this paper is free from shear locking and leads to accurate results for distorted element shapes. The transverse shear strain is formulated by the assumed natural strain (ANS) method, which ensures a constant distribution through the thickness and requires the introduction of shear correction factors. The transverse shear correction factors are calculated using a computational algorithm based on the static equilibrium and energy equivalence between the shear energy of the shell and the energy from three-dimentional theory. Material properties are varied continuously in the thickness direction according to different distributions. This finite element is used to study the post-buckling behavior of FGM structures and to investigate the influence of same parameters on post-buckling. Comparisons of numerical results among existing ones show the performance of the developed elements.