Nonlinear large-deflection dynamic buckling pressure of helically stiffened FG-GRC toroidal shell segments with porous core

Abstract

This paper presents an analytical investigation of the nonlinear dynamic buckling behavior of hollow-core functionally graded graphene-reinforced composite (FG-GRC) circular toroidal shell segments subjected to rapidly increasing external pressure. The shell structure is composed of FG-GRC face sheets and a porous core, and is reinforced by orthogonal and helical stiffeners. The mechanical response of the stiffeners is modeled using anisotropic beam theory, while a coordinate transformation approach is employed to incorporate the effects of inclined stiffeners into an equivalent smeared formulation. The governing equations are established based on Donnell’s shell theory in conjunction with von Kármán geometric nonlinearity, accounting for thermal effects and material gradation. By introducing an appropriate displacement field and stress function, the problem is reduced to a set of nonlinear ordinary differential equations through the Galerkin method. The dynamic response under linearly time-dependent pressure is obtained using a fourth-order Runge-Kutta scheme. The dynamic buckling load is determined according to the Budiansky-Roth criterion. Numerical results are presented to examine the influences of porous core configuration, graphene distribution patterns, stiffener arrangement, geometric parameters, loading rate, and temperature on the dynamic stability of the shell segments.