Edge Effects in Laminated Composites with Pin-Loaded Holes

Abstract

An analytical technique is developed for determining the three-dimensional edge effect stresses around pin-loaded holes in symmetric laminated composites. Based on the superposition principle of linear elasticity theory, the stress state around pin-loaded holes is divided into two parts, one the in-plane stress state determined using the classical laminated plate theory and the other the boundary-layer stress state arising from the edge effects that only exist in the vicinity of the holes. The equilibrium equations for boundary-layer stress state with zeroth-order approximation are written based on a set of power series expansions. A closed-form solution for the boundary-layer stress state with zeroth-order approximation is then obtained by imposing stress functions on the variational principle of complementary energy. Numerical results obtained using the present technique for cross-ply laminates are in good agreement with those obtained using finite element methods.