Sensing damage in carbon fiber and its polymer-matrix and carbon-matrix composites by electrical resistance measurement

摘要

Fatigue damage was sensed in real time incontinuous carbon fiber and its polymer-matrix and carbon-matrix composites by electrical resistance measurement in thefiber direction. In a polymer-matrix composite, fiber breakageovershadows fiber damage in causing the resistivity of thecomposite to increase irreversibly. In a carbon-matrixcomposite,fiber breakage and matrix cracking caused theresistivity to increase irreversibly, such that these twomechanisms cannot be distinguished. Fatigue damage wasdetected from 50% of the fatigue life onward for the polymer-matrix composite. and from 0% of the fatigue life onward forthe carbon-matrix composite.