CFRP is an electrically anisotropic material composed of conductive carbon fibers and insulator resins. In addition, CFRP has various applications such as unidirectional CFRP and woven-fabric CFRP. Although electrical conductivity of typical CFRP laminates of thickness direction has been measured, an interlayer conductivity between unidirectional CFRP and woven-fabric CFRP has not been measured. In the present study, the authors propose an identification method for the contact resistance of an interlayer between thin unidirectional CFRP and thin woven-fabric CFRP experimentally and analytically. In the measurement, electrical current is applied between two electrodes diagonally placed on the surface of unidirectional CFRP so that the bottom woven-fabric CFRP becomes a conducting path. The electrical potential in the middle area of the specimen is measured on the four center-electrodes. In FEM analysis, a virtual layer demonstrating for only contact resistance is inserted between two kinds of carbon fiber laminates and the electrical conductivity of thickness direction δZ that coincides with the measurement result is searched by trial and error. As a result, a contact resistance is measured between two different plies and the study finds that electrical conductivity of thickness direction is 1/10 times as small as one of transverse direction of unidirectional CFRP. Moreover, the authors calculate electrical conductivities of thickness direction of the interlayer between only unidirectional CFRPs or woven-fabric CFRPs analytically and find that contact resistance between unidirectional CFRP and woven-fabric CFRP is almost equal to one of unidirectional CFRPs.
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