Failure mechanism discrimination in carbon fibre-reinforced epoxy composites

Abstract To examine the possibility of discriminating between the various failure mechanisms which occur in carbon fibre-reinforced epoxy composites, unidirectional and crossplied specimens have been loaded to failure at various angles with respect to the fibre direction. The mechanisms which dominate the failure of unidirectional specimens under these loading conditions are known and the results have been compared with the amplitude of the acoustic signals recorded during loading. High amplitude signals were seen to originate from cracking of the matrix parallel to the fibres, whereas low amplitude signals were recorded from fibre breaks. These results have permitted an interpretation of the failure processes occuring in crossplied specimens.