Mechanism of Electrical Resistance Change of a Thin CFRP Beam after Delamination Cracking

This paper considers a detailed mechanism of the electrical resistance change observed after delamination cracking of a thin Carbon Fiber Reinforced Polymer (CFRP) laminate. For this laminate, the electrical resistance increases after delamination cracking, although the electrical resistance decreases after delamination cracking of a thick CFRP laminate. One of the proposed reasons for this difference is the residual strain relief caused by the delamination cracking. We report experimental and FEM analyses to investigate the effect of shut-off of the current path caused by delamination cracking, and the effect of piezoresistance caused by residual strain relief after delamination cracking. Residual strain relief was measured experimentally, and the results compared to the FEM results. On the basis of the FEM results the effect of the piezoresistance was estimated. It was found that the effect of the piezoresistance is small compared to the effect of the current shut-off for the thin CFRP laminate.