Full-field singular stresses in a composite laminate weakened by a cylindrical cavity: theory and experiment

Analytical and experimental investigation of strain fields arising in composite laminates in the vicinity of an open hole and ply interfaces was performed. The singular stress fields, arising at the ply interface and hole edge intersections, were analytically examined by using a novel technique based on superposition of an asymptotic and spline approximation solution. The moire interferometry technique, providing high spatial resolution and allowing rapid strain variations across a laminate thickness to be recorded, was utilized to experimentally measure the strain distributions throughout the thickness of a [+30(2)/-30(2)/90(4)](3s) laminate. The singular solution and the experimentally measured strain showed good agreement for most strain components with some discrepancy for the interlaminar normal strain component.