PSEUDO-DUCTILE BEHAVIOR OF UNIDIRECTIONAL FIBRE REINFORCED POLYAMIDE-12 COMPOSITE BY INTRA-TOW HYBRIDIZATION

Conventional carbon fibre reinforced plastics (CFRP) possess high specific strength and stiffness, can provide good chemical resistance and achieve long fatigue lives. However these materials are relatively brittle and have a low strain to failure and so structural failure can be catastrophic with little warning. In order to enhance the ductility of CFRP and change its catastrophic failure mode into a progressive one, carbon fibre tows with different failure strains were carefully selected and combined together into intra-tow hybrid reinforcement by using a gas-flow-assisted commingling process. This hybrid reinforcement was used to manufacture a polyamide-12 matrix composite using a polymer powder suspension impregnation method. By controlling the manufacturing parameters (speed and air flow rate in commingling process), a hybrid composite with significantly improved failure characteristics was obtained. Compared with corresponding single-fibre type composites, this hybrid composite has an improved tensile failure strain and still retains good tensile strength and stiffness properties.