Tailorable through-thickness fibre reinforcement in CFRP laminates with AFP via Repeated Segment Stacking

Composite laminates are vulnerable to delamination failure between the plies. With the increased usage of Automated Fibre Placement (AFP) to manufacture composites it is important to develop delamination mitigation strategies which are compatible with AFP manufacture. In this work we highlight the strategy of segmenting plies and stacking segment-by-segment via AFP, rather than ply-by-ply, to provide interlocks which resist delamination. We develop a novel category of segmented ply laminates, `Repeated Segment Stacking (RSS)’, to create significant through-thickness fibre reinforcements throughout the laminate thickness with AFP. We demonstrate successful AFP prototyping of the RSS mesostructures, including the ability to control the fibre undulation geometry. Our results show that low amplitude designs provide reinforcement across all horizontal planes whilst not significantly compromising in-plane performance, whilst increased amplitude designs mimic the impact resistant Herringbone structure of the Mantis shrimp’s dactyl club. Experimental testing to HVI, LVI, and CAI reveals the RSS designs reduce the delamination footprint and can contain damage at undulation boundaries. This first investigation of these original concepts demonstrates that the proposed RSS concept provides a promising development route for AFP-manufactured delamination resistant CFRP structures.

This repository contains raw data from the HVI, LVI & CAI tests and c-scan data post impact.