The influence of nonwoven interleaf architectures on the impact performance of composites

Structural properties of non-woven interleafs, such as their areal density and the linear density of the constituent fibres, have been identified as parameters that influence the interlaminar fracture toughness (IFT) of carbon fibre composites. We present an investigation of the influence of these properties on the damage resistance and damage toughness of composites, evaluated through impact and compression tests. The results show that when a non-woven interleaf is included within the composite, the damage resistance and tolerance of the composite is increased; the increase is greater for veils with higher areal density. These behaviours are consistent with those for IFT reported in the literature. Further, the composite interleaved with a veil absorbs more of the initial force of the impact, and results in a smaller measured impact area and has a higher residual compressive strength.