Impact perforation of carbon fibre reinforced plastic

Abstract

Low and high velocity impact tests have been undertaken on a series of CFRP laminates in order to examine the perforation process in a fibre reinforced composite. By sectioning and polishing many of the specimens a characteristic conical-shaped fracture zone has been highlighted, the basic form of which does not appear to vary with fibre stacking sequence or target thickness below 4 mm. The effect of varying certain geometrical parameters on the energy required to perforate the composite targets has also been examined. For conditions of low velocity impact loading where the structural response of the target is important, the areal dimensions of the target determine the perforation threshold energy. Conversely, under high velocity impact loading where the target response is highly localized, the perforation threshold appears to be independent of the areal geometry of the structure. By accounting for the dissipation of energy during the impact process, a perforation model has been developed in order to predict the influence of target thickness and specimen size on the perforation threshold. The accuracy of the model was then assessed by comparing its predictions with the available experimental evidence.