Experimental and finite element study of the electrical potential technique for damage detection in CFRP laminates

The electrical potential technique was applied to detect and locate impact damage in carbon fibre reinforced polymer (CFRP) plates of Hexcel T300/914 composite. The potential field across the surface of the laminates was measured using arrays of electrical contacts. A constant current of 100 mA was applied to the plate, and the changes in the potential distribution resulting from impact damage documented. These results have been compared with those calculated using 3D finite element simulation of current flow in CFRP laminates. The results show good agreement between simulation and experimental results and will permit detailed analytical studies of optimum network and current input configurations for the practical realization of a damage sensing system. A comparison of potential distribution on the top surface for damaged and undamaged laminates shows a substantial difference in the potential field around the impact damaged area. This could form the basis of a damage detection system.