The effect interleaving has on thin-ply non-crimp fabric laminate impact response: X-ray tomography investigation

To improve the damage resistance and tolerance of thin laminates manufactured with thin-ply non-crimp-fabrics, we interleaved non-woven veils into the interlaminar regions (two different types of co-polyamide veil were studied). We devised a low velocity impact and compression after impact (CAI) experimental campaign, where quasi-static indentation (QSI) tests at increasing loading displacements gave insight into the damage initiation and growth. For impact and QSI, the damage area was inspected using C-scan and X-ray micro-computed tomography. We observed that the melting temperature of the co-polyamide fibres has a key role on the impact response of thin-ply NCFs. Veils that melt during manufacturing avoided resin accumulation at the interfaces, decreased the damage area by more than 100% for a 14 J impact and improved CAI strength by up to 28%.