Buckling of laminated composite plate under biaxial loading conditions

The buckling behavior of laminated composite plates subjected to biaxial loading conditions was examined using theoretical, numerical and experimental approaches. For experimental work, a special plate specimen was developed. Deflection characteristics using different boundary conditions of the postbuckled plates were also experimentally investigated to obtain admissible analytical deflection functions and boundary conditions for the theoretical and numerical analyses. Non-linear finite element analysis (N-FEA) was carried out for the two types of boundary conditions, i.e., uniform pressure and uniform end-shortening, to approximate the actual boundary conditions of the plate in experiments. Comparing experimental results with the two N-FEA results for the two different boundary conditions, it was found that results using N-FEA with the uniform pressure loading condition agreed better with experimental results. Effects of flexural stiffness ratio, zeta, induced from the stacking sequence variation, were investigated through non-linear finite element analyses. It was found that zeta has an effect on the critical buckling load for high values of zeta. It also has an effect on the postbuckling behavior.