Abstract

An analytic approach for determining interlaminar stresses in rectangular [θ/-θ]s laminates subjected to an axial load has been adapted to the case of [θ1/θ2/θ3/θ4]s laminates. The coupling effects of each part of the laminate are compensated by the adjacent parts. In a first step, a half of the laminate is considered for determining forces and moments per unit length that prevent the global deformation of the whole symmetric laminate. Then, interlaminar stresses are computed applying the stress equilibrium equations and imposing the continuity of the stresses in the layer interfaces. The influence of the ply thickness and the stacking sequence of the laminate on the edge effect is analyzed by the analytical approach.

Abstract

The “edge effect” problem in laminates is a redundant topic in the literature since the seventies because of its influence on the reduction of the laminate strength. In previous works analytic solutions for angle-ply and quasi-isotropic symmetric laminates were obtained. In this work, a new model for obtaining solutions in the general case of symmetric laminates is presented. It is based on a new assumed displacement field in which the transverse bending of the laminate is not constrained. An strategy for solving the system of differential equations is proposed, as well as different hypotheses for the boundary conditions. Different solutions for the interlaminar stresses can be derived from the proposed technique.