Nonlinear thermomechanical buckling and postbuckling analysis of sandwich FG-GPLRC complexly curved caps and circular plates with porous core

This paper presents an analytical approach for the nonlinear buckling and postbuckling responses of functionally graded graphene platelets-reinforced composite (FG-GPLRC) complexly curved caps with porous core under uniformly distributed thermal and external pressure resting on the nonlinear elastic foundation using the first-order shear deformation theory (FSDT) with the geometrical nonlinear sense of von Kármán. Four cap types are considered including spherical caps, ellipsoid caps, sinusoid caps, and paraboloid caps in this paper, and the results of circular plates can be obtained by the radius of the shell’s curvature approaches infinity. The graphene platelet (GPL) nanofillers are distributed into the polymer matrix of two coatings according to the uniformly and functionally graded laws in the thickness direction. The Galerkin method is applied and the expressions of thermal critical buckling loads and thermal and mechanical postbuckling curves of the caps are determined. The effects of cap types, geometrical properties, imperfect deflection, and nonlinear elastic foundations on the critical buckling loads and postbuckling curves of the caps and plates are discussed in numerical results.