LOADING RATE AND TEMPERATURE-DEPENDENCE OF FLEXURAL BEHAVIOR OF UNIDIRECTIONAL PITCH-BASED CFRP LAMINATES

The mechanical behaviour of polymer resins heavily depends on time and temperature, in a manner which is termed viscoelastic behaviour. It i s therefore presumed that the mechanical behaviour of fibre-reinforced plastics (FRPs) also depends on time and temperature because of the v iscoelastic behaviour of the matrix resin. The flexural static and fat igue behaviour of three kinds of unidirectional pitch-based CFRP lamin ates, which are a combination of two types of resin and two types of f ibre, were evaluated at several levels of loading rates and constant t emperatures. The flexural static and fatigue behaviour was found to be remarkably dependent on time and temperature. The time-temperature su perposition principle of the mechanical behaviour of the matrix resin held for the flexural fatigue strength as well as the flexural static strength of the CFRP laminates. Clearly, the flexural static and fatig ue behaviours of the CFRP laminates matrix resin.