Buckling and postbuckling of embedded sandwich moderately thick plates with functionally graded graphene nanoplatelet-reinforced porous core and metallic face sheets

In this study, the buckling and postbuckling of embedded sandwich moderately thick rectangular plates with functionally graded graphene platelet-reinforced composite porous core and metallic face sheets are studied. The considered plates are subjected to the uni-axial and bi-axial compressive loadings. Based on the Reddy's third- order shear deformation plate theory and the von Ka<acute accent>rma<acute accent>n large deflection assumptions, the weak form of discrete nonlinear equilibrium equations of considered sandwich porous plates are derived using the principle of minimum total potential energy. Then, by solving the linear part of achieved equations as an eigenvalue problem, the critical buckling loads and associated modeshapes are obtained. Then, to obtain the equilibrium postbuckling path of sandwich FG-GPLRC porous rectangular plates with different boundary conditions, the obtained critical bucking loads and modeshapes are considered as the initial guess as well as incrementally applying the applied in-plane compressive load rise. Finally, using the pseudo arc-length technique and modified Newton-Raphson scheme, the set of nonlinear algebraic equations is solved and the equilibrium postbuckling path is obtained. A detailed parametric study is conducted to study the effects of various parameters such as the sandwich core thickness-to-metallic face sheet thickness ratio, porosity coefficient/distribution pattern, GPL weight fraction/ distribution pattern and boundary conditions on the critical buckling load and postbuckling strength of FGGPLRC porous plates.