Mode-I Interlaminar Fracture Toughness in Unidirectional Carbon-fibre/Epoxy Composites

High performance carbon fibre/epoxy composites, which are increasingly used for
structural applications are susceptible to delamination. In response to this problem,
the mode-I interlaminar fracture toughness of unidirectional carbon/epoxy
laminates has been studied under tensile loading by using a double cantilever beam
(DCB) specimen. The fracture energy is deduced from the data according to the area and
the compliance methods. The morphology was explained through thermal analysis using
DMA and fractography from scanning electron microscopy (SEM). Results showed
improvement in high temperature moulding compound (HTM) system with 180°C cure in
terms of interlaminar fracture toughness. There is also an improvement in MTM and LTM
systems. SEM micrographs revealed their excellent delamination resistance as good
crack stoppers with the evidence of strong fibre/matrix interface. For MTM systems GIc
values dropped after post curing. This reduction was significant for MTM49-3 but not so
much in the case of MTM49-7 laminate. On the other hand, the GIc for LTM45-1 did not
seem to be affected by post curing at elevated temperature.

Citation:
Barikani, M., Saidpour, H. and Sezen, M. (2002) ‘Mode-I Interlaminar Fracture Toughness in Unidirectional Carbon-fibre/Epoxy Composites’ Iranian Polymer Journal, 11 (6), pp. 413-423..