A comparative assessment of 3D wovens and non-crimp fabrics under three point bending

Traditional 2D laminated composites are particularly susceptible to impacts, which load the composite through the thickness and generate delaminations. Various methods of through thickness reinforcement such as; z-pinning, stitching and 3D weaving have been designed to combat these loads. To comparatively assess both the in- and out-of-plane performance of leading edge resin-infused dry fiber composites, three point beam test were performed at a range of span to thickness ratios and static and dynamic loading rates. Tested materials include two tufted non-crimp fabrics and three 3D woven material systems. For high interlaminar loads 3D wovens and NCFs demonstrated comparable performance, but as the relative amount of in-plane loading was increased, the relative strength of the warp aligned 3D woven was reduced significantly. In terms of damage resistance, both tufts and through thickness warp tows had a measurable impact on the post-failure energy dissipation. Qualitatively the NCF consistently failed through extensive delamination, whereas the 3D woven showed localized matrix and fibre damage between the support and loading rollers. This fundamental change of failure behavior may have a significant effect on the way these two material systems respond to real-world impact events.