Impact behaviour of quasi-isotropic graphite-peek laminates

An important consideration in the design of composite material structures is their response to the low velocity impact loadings, that may occur during service and maintenance. In order to develop general models addressing the issues of damage tolerance and resistance, precise understanding of the nature and extent of damage and identification of the dominant fracture modes are essential. In this study instrumented drop-weight impact tests were carried out to examine the impact behaviour of quasi-isotropic graphite/peek laminates, which are characterized by higher resistance to delamination, compared to epoxy based composites. The sequence of damage progression and its relationship with impact and absorbed energy were investigated by means of a detailed damage analysis, conducted with various techniques (X-radiography, ultrasonics, optical microscopy).