Deformation of notched carbon fibre composites

Abstract

A recently developed moiré technique was used to study in-plane surface displacements in notched carbon fibre composite plates under a tensile load. Elastic strains near a transverse notch in a unidirectional specimen were compared with the theoretical results for a homogeneous orthotropic sheet. Displacements and strains were obtained near shear cracks which developed at the notch tips in unidirectional and crossplied specimens. Shear strains along the crack were attributed to fibres tying the crack faces together and frictional forces. Values for the fracture energy GII were obtained.