Interlaminar Shear Stresses Around Internal Elliptical Cylindrical Holes Weakening Edge-Loaded Cross-Ply Plates

Abstract

A semi-analytical postprocessing method, termed the equilibrium/compatibility method, is employed for computation of hitherto unavailable through-thickness variation of interlaminar shear stresses in the neighborhood of the bilayer interface circumferential reentrant corner line of an internal (part-through) elliptical cylindrical hole weakening an edge-loaded laminated composite plate. A C 0 -type triangular composite plate element, based on the assumptions of transverse inextensibility and layerwise constant shear-angle theory, is used to first compute the in-plane stresses and layerwise through-thickness average interlaminar shear stresses, which serve as the starting point for computation of through-thickness distribution of interlaminar shear stresses in the vicinity of the bilayer interface circumferential reentrant corner line of the internal hole. The errors in the same stresses computed by the conventional equilibrium method are more severe in the presence of the bilayer interface circumferential reentrant corner line singularity arising out of the internal (part-through) elliptical cylindrical hole than their circular counterparts, and are, as before, found to violate the interfacial compatibility condition. The computed interlaminar shear stresses can vary from negative to positive through the thickness of a cross-ply plate in the neighborhood of this kind of stress singularity.