On compressive failure of multidirectional fibre-reinforced composites: A fractographic study

The compressive failure of multidirectional carbon fibre-reinforced composites is investigated in this paper. Cross-ply and multidirectional compact compression IM7/8552 specimens were tested to deduce the failure mechanisms that occurred during compressive loading. The experimental results and the subsequent fractographic analysis revealed that the stacking sequence had a significant effect on the performance of multidirectional composites under compression. Delamination and in-plane shear fracture were the dominant failure mechanisms both in cross-ply and multidirectional configurations. While multidirectional configurations exhibited a stiffer response and higher failure load compared to cross-ply configurations, they were also more prone to delaminations and post-failure damage. Multidirectional laminates also exhibited significantly more complex fracture morphologies, which made the failure process interpretation more difficult. The sequence of events that lead to global fracture in multidirectional fibre-reinforced composites is presented.