Torsional Fatigue Property of Carbon Fiber Obtained from the Different Burning Temperature

摘要

Generally, the decrease in modulus that originates in fatigue is not observed in inorganic fibers such as carbon fiber and graphite fiber. On the other hand, Kevlar, PBO, and Vectran that are organic fibers show a very remarkable fatigue behavior. The mechanical property of these fibers becomes clearer because it measured with a single fiber rather than measurement with the bundle. As for the mechanical property of these fibers, measuring it with a single fiber becomes clearer from the fiber bundle. We examined the torsional fatigue property of the single carbon fiber in detail. The following two points were clarified as a result. (1) As for carbon fiber, the decrease in modulus by torsional fatigue is not observed. However, modulus in the appearance decreases because torsional fatigue causes the peeling off of the skin layer of the single carbon fiber surface. The decrease in modulus was remarkable like a carbon fiber with a higher burning temperature. (2) Tensile modulus after torsional fatigue maintained almost the same level after fatigue test. However, breaking strength decreased, and this is a defect in the fiber caused by torsional fatigue.