Influence of veil interleave distribution on the delamination resistance of cross-ply CFRP laminates under low velocity impact

This paper focuses on the influence of polyphenylene sulfide (PPS) veil distribution within unidirectional carbon fibre reinforced polymer (CFRP) laminates under low velocity impact (LVI). Tests were conducted on a baseline layup of (0/90)(7s) modified with various levels of veil interleaving at the middle or the outer plies. The results demonstrate that veil interleaving can reduce and migrate the damage from predominantly inter-laminar to intra-laminar for veils positioned in the outer plies. The interleaved configurations also display differences in the impact stiffness [1] after the Delamination Threshold Load (DTL), implying the level of damage is lower than those with fewer veils and those positioned at the mid-level neutral plane. Interesting changes in the impact force history are also observed where a smoothing effect around the DTL is achieved through interleaving. Fracture migration effects are also considered and provide a significant insight into the damage characteristics when using CFRP laminates with interleaved PPS veils under LVI.