Electrical Resistance Change of Self-Sensing CFRP Laminates during Cyclic Loading

Abstract

Self-sensing Carbon Fiber Reinforced Plastics (CFRP) is one of the attractive multifunctional composites. That multifunctional composite has structural strength/stiffness and sensing function using electrical resistance changes. For the self-sensing, electrical contact between the lead wire and the carbon fibers is the most important issue. The present study focuses on the effect of the long term cyclic loading of lower applied strain range than the fatigue damage initiation level. Cyclic loading tests of the lower applied strain range are performed in the present study with measuring electrical resistance changes. The temperature change compensation method is proposed here for the long term tests. As a result, the electrical contact resistance at the copper electrode increased with the increase of cycles. That means the electrical change at the electrodes must be considered for the long-term self-sensing monitoring system. Moreover, angle-ply laminates has plastic deformation caused by shear loading, and that causes electrical resistance decrease during the cyclic loading.