Evaluation of a damage-mechanics approach to the modelling of notched strength in KFRP and GRP cross-ply laminates

This paper describes the experimental observation of damage growth and failure in a range of notched cross-ply laminates in Kevlar-fibre and glass-fibre-reinforced polymer (KFRP and GRP). In each material, the transverse ply thickness was systematically varied, leading to different densities of transverse ply cracks and changes in the evolution of damage in the load-bearing 0° plies. The behaviour in static and fatigue loading was compared with that observed in carbon-fibre-reinforced polymer (CFRP) and used previously as the basis of a damage-mechanics model for predicting the residual strength. The behaviour of KFRP resembled that of CFRP, with a well-defined damage pattern, but in GRP the damage was variable and spread wide from the notch. This was attributed to fibre failure in the 0° plies, which reflected an interaction between the transverse ply cracks and the 0° plies.