The effects of strain-rate and temperature on the interlaminar fracture toughness of interleaved PEEK/CF composites

The effect of interleaving on the interlaminar fracture behaviour of unidirectional and woven-fabric fibre composites based upon continuous carbon fibres (CF) and poly(ether ether ketone) (PEEK) has been investigated over a wide range of temperature and crack speed. The fracture data obtained from mode I and mode II tests have been analysed using the time-temperature equivalence postulate and the results are discussed in terms of fracture micromechanisms. The insertion of a resin-rich layer between laminae was found to increase significantly the fracture resistance of the composites, whitout altering its dependence on crack speed.