Detection of Matrix Cracking of CFRP Using Electrical Resistance Changes

Abstract

stract. Effect of thickness of 90o-plies on a method for detection of matrix cracking of CFRP inates is investigated here. Three types of cross-ply CFRP laminates are adopted here: [0/90/0]T, 90]S and [0/902]T. Tensile cyclical loading tests are performed with increasing the maximum load plied cyclic loading. Electrical resistance changes are measured using silver paste electrodes by ans of a four-probe method. As a result, it was revealed that residual electrical resistance under mplete unloaded condition was not applicable for an indicator of creation of matrix cracking in the ck cross-ply laminates. For the thick cross-ply laminates, tensile residual stress in the middle o-plies is smaller than that of the thin laminates. This small tensile residual stress causes crack sure when the specimen is completely unloaded. When the cross-ply laminates are reloaded, the ctrical resistance increased rapidly with the small increase of load due to the opening of matrix cks. From this result, we proposed a new method for detections of matrix cracking using the rapid rease of electrical resistance in small reloading.