Transient energy absorption characteristics and interlaminar fracture toughness of glass/epoxy composites with recycled milled fillers

Advanced composites are increasingly used in aircraft and automotive structures, highlighting the need to address delamination, a critical failure mode caused by interlaminar weakness. Also the end-of-life of composite material is challenging. The interlaminar fracture toughness, impact resistance and residual flexural performance of glass/epoxy composites with recycled milled carbon fibre (rmCF) and recycled milled Kevlar fibre (rmKF) fillers are examined in this study. This novel approach blends recycled fillers (rmBF) and tests their effects on interlaminar fracture toughness, crash performance, and residual strength using modes I, II, mixed mode I/II and drop weight impact tests. Filler-loaded samples show a remarkable increase in fracture toughness, with initiation improvements of 319, 31 and 200% and propagation improvements of 83, 14.4 and 172.3% in modes I, II and mixed mode. Up to 15% improvement was seen in the impact performance index and a 10% increase in residual strength. FTIR is used to correlate the effects of rmCF, rmKF and rmBF on interfacial properties, while SEM micrographs show how the filler-modified matrix toughens interlaminar fractures. This research helps improve composite material performance and sustainability.