Electrical Resistance Change of CFRP under a Compression Load

Abstract

Many researchers adopt electrical resistance change (ERC) methods to detect damage in Carbon Fiber Reinforced Plastic (CFRP) laminates. They usually apply the method under tensile or bending loads. For compression tests, a block type specimen is used. The block type specimen, however, is too thick to obtain a uniform electrical current. This study starts with the design of a compression test specimen with uniform electrical current using a sandwich beam specimen. The four-point bending tests revealed that the piezoresistivity of the compression tests was the same as that of the tension tests. Using a three-point bending test, fiber-micro-buckling was obtained, which caused an increase in electrical resistance with residual compression strain. Non-linear behaviors observed during cyclic loading tests were investigated, and it was revealed that the plastic deformation at the loading point had large effect.