Effects of the imbedded optical fibre sensors on the fracture toughness of composite materials

An initial investigation of the influence of imbedded optical fibres upon the damage resistance of Kevlar/epoxy has been undertaken. The propagation of delamination and transverse cracks through the Kevlar/epoxy laminate specimens in presence of imbedded optical fibres was separately observed by use of the backlighting techniques. The optical fibres appeared to act as crack energy dissipators and, thereby, to reduce the rate of crack propagation. Measurements of the critical energy release rate were then carried out and quantitative results were obtained which substantiate the above observations. In effect the presence of imbedded optical fibres appeared to enhance the fracture toughness of the composite. In no case were the imbedded optical fibres found to have any detrimental on Kevlar/epoxy.;Experimental results from both qualitative and quantitative tests are presented and discussed. A proposal for further research is also presented.