EDGE EFFECTS IN LAMINATED COMPOSITES WITH PIN-LOADED HOLES

An analytical technique is developed for determining the three-dimensi onal edge effect stresses around pin-loaded holes in symmetric laminat ed composites. Based on the superposition principle of linear elastici ty theory, the stress state around pin-loaded holes is divided into tw o parts, one the in-plane stress state determined using the classical laminated plate theory and the other the boundary-layer stress state a rising from the edge effects that only exist in the vicinity of the ho les. The equilibrium equations for boundary-layer stress state with ze roth-order approximation are written based on a set of power series ex pansions. A closed-form solution for the boundary-layer stress state w ith zeroth-order approximation is then obtained by imposing stress fun ctions 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 .