Nonlinear Stability of Sandwich FG-GPLRC Shallow Spherical Caps and Circular Plates with Porous Cores Based on FSDT –A Stress Function Approach

Abstract

This paper presents a study on the nonlinear stability of shallow spherical caps and sandwich circular plates made from functionally graded graphene platelet-reinforced composite (FG-GPLRC) with porous cores. The structures are subjected to external pressure, uniform thermal loading, and are resting on a Winkler elastic foundation. The First-Order Shear Deformation Theory (FSDT), incorporating von Kármán-type geometric nonlinearity is employed to formulate the governing equations. A novel approach using stress functions is developed to model the structural behavior. Furthermore, the total potential energy expressions are derived, and the Ritz energy method is utilized to obtain the equilibrium equations. A comprehensive numerical investigation is conducted to analyze the effects of geometric and material parameters, porosity coefficients, and foundation stiffness, with detailed discussions provided.