Failure mechanisms and damage evolution of laminated composites under compression after impact (CAI): Experimental and numerical study

The damage tolerance of Carbon Fibre Reinforced Polymer (CFRP) to Barely Visible Impact Damage (BVID) is a critical design limiter for composite structures. This study investigated the key driving mechanisms and damage evolution of the compressive failure of laminated composites containing BVID using compression after impact and indentation (CAI) tests. Experiments were carried out on two similar quasi-isotropic laminates: [452/902/02/−452]2S and [45/90/0/−45]4S. Matrix cracking and delaminations were introduced by either low-velocity impact or quasi-static indentation tests prior to the CAI tests. The full-field displacement during CAI as well as the moment of rupture was captured by 3D Digital Image Correlation (DIC). The effect of ply-blocking and influence of factors, such as impact energy, delamination area and surface indentation, on compressive failure was studied. Previously validated high-fidelity finite element (FE) numerical models for the indentation and impact events were then used to investigate the damage evolution during CAI failure.