Nonlinear buckling and post-buckling analysis of shear deformable stiffened truncated conical sandwich shells with functionally graded face sheets and a functionally graded porous core

In this study, the nonlinear buckling and post-buckling analysis of stiffened truncated conical sandwich shells with functionally graded face sheets and a functionally graded porous core resting on the Winkler–Pasternak elastic foundation subject to a uniform axial compressive load has been investigated. Shells are reinforced by functionally graded material stringers and rings, in which the change of spacing between stringers in the meridional direction also is taken into account. The stability equations of the shell are derived based on the first-order shear deformation theory with a von Karman–Donnell type of kinematic nonlinearity and the smeared stiffener technique. Those equations are solved by the Galerkin method to determine the effects of stiffeners, shell characteristics, material properties, porosity coefficient, and elastic foundation on the critical buckling load and for analyzing the post-buckling load–deflection curves. The approaches are verified with the known results in the literature.