A model for the reduction in compression strength of continuous fibre composites after impact damage

Abstract

The post-impact compression behaviour of three different laminates has been measured experimentally. It was observed that normalized values of post-impact compression strength of dissimilar laminates were similar when considered as a function of damage width. This observation has been investigated using a finite element model. The model is based on the hypothesis that failure in post-impact compression occurs via the stress magnification arising from the presence of the damaged zone. The implied values of the modulus of the damaged zone are deduced. These values are found to be dependent on the damage width. The model provides an explanation for the failure in compression of impacted plates that does not invoke fracture mechanics concepts and is therefore compatible with experimental results that indicate comparable performance from laminates that exhibit different G IC and G IIC values.