Engineering the translaminar fracture behaviour of thin-ply composites

Bio-inspired patterns of micro-cuts perpendicular to the fibre direction in thin-ply CFRP laminates have been used to increase the translaminar fracture toughness of the material. An analytical model to predict the probability of bundle pull-out during translaminar crack propagation was developed and validated through an experimental parametric study. The model was used to design three hierarchical patterns of micro-cuts and the patterns have been tested using Compact Tension specimens. The increase in fracture toughness for the three patterns was +15%, +60% and +214% when compared with the baseline material, thereby demonstrating the potential of engineering the fracture surface in CFRPs through well-designed patterns of micro-cuts to improve the damage tolerance of the material.