On the mix-mode fracture of carbon fibre/epoxy composites interleaved with various thermoplastic veils

This work studied the mix mode-I/II fracture behaviour of an aerospace-grade carbon fibre/epoxy composite that was interlayer-toughened by Polyamide-12 (PA), Polyphenylene-sulphide (PPS), Polyimide (PI), Polyethersulfone (PES) and Polyethylenimine (PEI) fibres. During laminate curing process, PA fibres melted, PPS PI kept in their original form PES PEI dissolved epoxy matrix. resulted different toughening mechanisms veils for laminates, which using a cracked lap-shear test. The main were observed to be plastic deformation failure thermoplastic resin meltable veils, fibre debonding bridging intact particle void growth dissolvable veils. experimental results revealed mechanism superior toughness enhancement, followed mechanism. For instance, interleaving increased mix-mode propagation energy laminates 345% 171%, respectively. However, performance poor, since crack mainly propagated at vicinity around interlayer/laminate interface.