Effect of resin and fibre properties on impact and compression after impact performance of CFRP

The effect of resin and fibre properties on composite impact, compression after impact (CAI) and mode II energy release rate (G(IIC)) performance has been studied. Impact events were instrumented to record values of P-c, the critical load for initiation of impact damage. Impact response of the laminates was strongly influenced by the fracture toughness of the resin. In contrast, use of high strength and high stiffness fibres did not improve the resistance to impact. The differences in impact and CAI response of the laminates were largely a consequence of the impact damage created at the damage threshold, P-c, rather than of the differences in delamination growth. As a strong correlation was found between G(IIC) values measured by delamination tests, and those calculated from measurements of P-c, it is suggested that instrumented impact testing may be a more convenient way of determining G(IIC) in CFRP laminates than delamination tests. (C) 2002 Published by Elsevier Science Ltd.