STRESS DECAY IN AN ORTHOTROPIC HALF-PLANE UNDER LOCAL SELF-EQUILIBRATED EDGE LOADING

Abstract

An exact solution is presented for the stresses in a specially orthotropic half-plane under a localized, symmetric, self-equilibrated combination of uniform normal edge loadings. “Smeared” orthotropic material properties are used to represent a broad range of balanced angle-ply graphite-epoxy laminates. Expressions for the three stresses in the half-plane are presented for isotropic material and for two orthotropic material families that contain many of the practical laminates. Particular attention Is given to the diffusion of the edge loading into the half-space and to the shear stresses caused by the discontinuous edge loading, both of which are strongly influenced by material properties. Of special interest to designers of composite structures may be a simple approximate formula, in terms of material properties, which is proposed for a lower bound on the normalized 90%-decay distance for the normal stress. Also, the results serve as further illustration of the fact that the meaningful application of Salnt-Venant's principle to specially orthotropic materials requires knowledge of their elastic properties.