FATIGUE-INDUCED DAMAGE MECHANISMS IN CARBON FIBER-REINFORCED PLASTIC COMPOSITES

A study has been made of the damage mechanisms introduced by the fatigue process in two high-performance carbon-fibre-reinforced plastic laminates, XAS/914 and T800/5245. A series of experiments has been carried out to evaluate systematically the fatigue damage mechanisms that occur at different cyclic stress levels during repeated tension loading. The state and development of damage were mainly investigated by means of edge replication. Microscopy studies were used in support of the non-destructive evaluation methods. Important information relating to the onset of various types of fatigue-induced damage is presented in the form of schematic ''damage maps''. When the differences in strength of the two materials are taken into account, it appears that the XAS system exhibits fatigue resistance superior to that of the T800 system.