An investigation of the damage tolerance of carbon/Benzoxazine composites with a thermoplastic toughening interlayer

The results of an experimental analysis of the damage tolerance of carbon/Benzoxazine laminates subjected to a 30 J impact, compression after impact (CAI) and open-hole compression (OHC) are presented herein. Four configurations of quasi-isotropic laminate with interlaminar polyamide (PA) fibre veils are studied. Damage areas were examined using X-ray imaging and micro-computed tomography (μCT). It was found that interlaminar veils decreased damage area by up to 36% for a 30 J impact. The veils, however, caused the formation of long, cylindrical voids due to retention of the resin within the veils which did not permit percolation into the fibre tows. Despite this, the veils increased the CAI strength from 45% of the undamaged compressive strength to 64%. The OHC response of three types of laminates was found to compare well with commercially available carbon/epoxy systems qualified for use in aircraft structures, but was not significantly affected by the interlaminar veils.