Improved Energy Absorption in 3D Woven Composites by Weave Parameter Manipulation

Kurzfassung

3D woven composites show significantly improved out-of-plane properties over traditional 2D laminates. This high through-thickness reinforcement is desirable in crashworthiness applications where crushing energy can be increased by composites’ improved interlaminar toughness. However, their use in practical applications is stunted by the poor understanding of how small variations in weave parameters, whether intended or not, affect the performance of these materials. Here, we demonstrate that small changes in textile properties, in this case pick density and float length have a knock-on effect that can greatly improve or diminish the crush performance of a 3D woven layer-to-layer structural fabric. Quasi-static and dynamic energy absorption values up to approximately 95J/g and 92J/g respectively are achieved. Crush performance is investigated on omega-shaped coupons, under both quasi-static and dynamic loading conditions with crush rates between 2mm/min and 8.5m/s. The failure mechanisms present during progressive crush under quasi-static loading transitions between more expected brittle dominated failure and ductile dominated failure, which is more typical of metals under similar loading conditions. Whereas when dynamic loading is considered, the materials present a more typical splaying failure event. As a result, additional exploration of the three-point bending response of these varied architectures is presented as a means of further explaining the interplay between lamina bending and progressive folding/micro-buckling in these materials. The effect of the weave’s architectural alterations on physical composite properties such as weight, density and conformability to shape is also investigated.