Residual strain relief effect on the electrical resistance measurement for delamination monitoring of carbon/PEEK laminates

Damage, such as delamination and fi ber breakages, to the carbon/epoxy laminates can be detected by measuring electrical resistance changes caused by the damage. The resistance changes result from the electrical current path being impeded and deformation of the composites relating to piezoresistivity. In the present study, the effect of the residual strain relief due to delamination is investigated analytically and experimentally for two different stacking sequences and it is confi rmed that piezoresistivity has a signifi cant effect on the measured electrical resistance change in the electrical resistance change method.