CORRELATION OF CHANGE IN ELECTRICAL-RESISTANCE WITH STRAIN OF CARBON-FIBER-REINFORCED PLASTIC IN TENSION

A study was carried out on the variation in the electrical resistance of carbon fiber-reinforced unsaturated polyester/polyurethane (UP/PU) IPN composites during static tension, cyclical loading, and unloading in tension. The resistance was found to vary nonlinearly with strain a nd increase abruptly when the composite approached the fracture. Under a certain constant tension, the change in electrical resistance showe d time dependence, and it is suggested that the creep of the IPN netwo rk imposed an impact on the variation of resistance. The resistance pr obing revealed that carbon fiber-reinforced plastic can function as a sensor that is capable of self-diagnosing the fatal fracture in compos ites. (C) 1996 John Wiley & Sons, Inc.