Thermal post-buckling behaviour of laminated plates using a shear-flexible element based on coupled-displacement field

Post buckling behaviour of rectangular laminated plates subjected to thermal loads is investigated in this paper. For this purpose, a four-node, lock-free, rectangular composite plate finite element having six degrees of freedom per node viz three translations, two bending rotations about x- and y-axes and a twist is developed. The element is based on a bicubic representation of the transverse displacement field. The field descriptions for other variables are derived using equilibrium equations of strips along x- and y-axes of the plate. As a result field descriptions involve material properties apart from the usual geometric variables. 3×3 Guass Quadrature formula is employed to compute the elemental matrices. Though an exact integration rule has been employed, the element is free of shear locking even in the extreme thin plate regimes. The effect of boundary conditions, aspect ratio, number of layers and lay-up sequence on the post-buckling behavior is studied in detail. The numerical examples solved herein reveal the possibility of secondary bifurcations from the primary post-buckling path.