External pressure buckling of composite sandwich conical shells with variable skin thickness

Abstract

In this paper, an analytical model is developed to investigate the buckling analysis of the composite sandwich conical shell with variable skin thickness under lateral pressure loading. This problem involves composite shells, which are produced during the filament-winding process, where the skin thickness varies through the length of the shell. An effective smeared method is employed to reduce the reinforced lattice core into a layer. This is done by analyzing forces and moments on a unit cell. Therefore, equivalent stiffness parameters of reinforced lattice core are determined. By superimposing stiffness parameters due to the lattice core with those of the inner and outer skins, the equivalent stiffness of the sandwich panel will be obtained. Governing equations are established based on the first shear deformation theory. The power series method is used to extract the buckling load of the stiffened shell. To verify achieved results, a 3D finite element model is provided. Comparisons showed that the analytical solution is qualified enough to study the buckling behavior of the composite sandwich conical shell. Through this study, the effects of a set of important parameters like stiffener orientation angle, number of stiffeners, semi-vertex angle, and skin lamination are investigated.