Abstract

Composite structures exhibit many different failure mechanisms, but attempts to model composite failure frequently make a prioriassumptions about the mechanism by which failure will occur. Compressive tests were conducted at Bristol University on composite specimen manufactured with dropped plies which created wout-of-plane waviness defects. Significantly different failure mechanisms were observed for each case, so detailed finite element models of these experiments were developed which included competing failure mechanisms. The model predictions correlate well with experimental results – both qualitatively (location of failure and shape of failed specimen) and quantitatively (failure load). The models are used to identify the progression of failure during the compressive tests, determine the critical failure mechanism for each configuration, and investigate the effect of cohesive parameters upon specimen strength. This modelling approach which includes multiple competing failure mechanisms can be applied to predict failure in situations where the failure mechanism is not known in advance.