Abstract
An impact load on a thick carbon fiber reinforced plastic (CFRP) plate usually causes a dent. The dent results in a decrease of electrical resistance in the thickness direction. Our previous papers demonstrated the effect of the dent in the measurement of electrical resistance change of a thick CFRP plate subjected to impact loading. The present paper focuses on the mechanism of decrease of the electrical resistance caused by a dent. Experiments were performed to measure local fiber volume fraction after various loading. The observation revealed that the dent is made by plastic deformation of the matrix under compression loading at an impactor. This deformation cause slight increase of fiber volume fraction. The slight increase of the fiber volume fraction causes significant increase of electric conductance in the thickness direction.
