Author(s)

Akira Todoroki, Daichi Haruyama, Yoshihiro Mizutani, Yoshiro Suzuki, Tesuo Yasuoka

Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, Tokyo, Japan.
Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, Tokyo, Japan..

Self-sensing multifunctional composite has sensing function using electrical resistance changes. Carbon Fiber Reinforced Polymer (CFRP) composite is one of the self-sensing multifunctional composites. For the reliability of 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 cyclic loading of lower applied strain range than the fatigue damage level. As a result, the electrical contact resistance at the copper electrode increased with the increase of cycles. That means that the electrical change at the electrodes must be considered for the long-term self-sensing monitoring system. When a four-probe method is used to measure the electrical resistance, the contact resistance effect is minimized. Moreover, angle-ply laminates have plastic deformation caused by shear loading, and that causes electrical resistance decrease during the cyclic loading. Cross-ply laminates of CFRP composites have no electrical resistance increase without damage. Quasi-isotropic laminates of CFRP composites, however, have electrical resistance decrease with the increase of the number of cycles because of the plastic deformation of the angle-ply laminates.

Carbon Fiber; Electrical Properties; Non-Destructive Testing; Smart Materials

A. Todoroki, D. Haruyama, Y. Mizutani, Y. Suzuki and T. Yasuoka, "Electrical Resistance Change of Carbon/Epoxy Composite Laminates under Cyclic Loading under Damage Initiation Limit," Open Journal of Composite Materials, Vol. 4 No. 1, 2014, pp. 22-31. doi: 10.4236/ojcm.2014.41003.