Estimation of interlaminar stresses in fibre reinforced composite cylindrical shells

Abstract

A C⁰ finite element formulation for flexure-membrane coupling behavior of symmetric and asymmetric laminated cylindrical shells based on a higher-order displacement model is presented. This theory incorporates a realistic nonlinear variation of displacements through the shell thickness, and eliminates the use of shear correction coefficient/s. The discrete element chosen is a nine-noded quadrilateral with nine degrees of freedom per node. The solutions are obtained through two formulations: (1) the geometrically thin shell formulation, based on the assumption that the ratio of thickness to radius of the shell is very much less than unity, and (2) the geometrically thick shell formulation, in which (h/R)²«1. In these formulations, the in-plane stresses are obtained via constitutive relations. Reliable estimates of interlaminar stresses from equilibrium equations are obtained. A finite difference scheme maintaining the continuity of interlaminar stresses across the shell thickness is developed and used. The results obtained are compared with available elasticity, closed-form and other finite element solutions.