To measure residual electrical resistance during and after straining was found to be a promising method for foreseeing the fracture of the CFGFRP (carbon fiberglass fiber reinforced plastics) composites containing carbon fiber bundles. On loading, the electrical resistance of the CFGFRP composites increased nonlinearly with increasing strain. Permanent, residual electrical resistance was reproducibly observed even after the removal of load, and the change was dependent on the maximum strain applied. Two kinds of PAN-based high strength carbon fiber and PAN-based high modulus carbon fiber were evaluated for their suitability for foreseeing the fracture of the CFGFRP composites. The former showed a larger residual electrical resistance than the latter.
