Carbon fiber polymer-matrix structural composites for sensing

Carbon fiber polymer-matrix structural composites can sense its own strain, stress or damage due to the effects of these parameters on the electrical resistivity of the composite. Sensing is particularly effective under flexure, as indicated by the surface resistance of either the compression or the tension side. It is also effective under through-thickness compression (which is relevant to fastening), as indicated by the longitudinal resistance of the composite. Moreover, it is effective under impact, as indicated by the contact resistivity of the interlaminar interface. Sensing by resistance measurement is more effective than sensing by potential measurement, although the latter is more amenable to spatially resolved sensing. For resistance measurement, the four-probe method is more effective than the two-probe method. This paper provides a review of this subject.