Role of matrix resin on the flexural static behavior of unidirectional pitch-based carbon fiber laminates

The flexural fracture behavior of unidirectional CFRP laminates using three types of thermosetting resin as matrices with a pitch-based carbon fiber, was investigated by three-point bending tests over a wide range of temperature and deflection rate. By comparing the results of the three types of CFRP laminates, the characteristics of these CFRP laminates were clarified. The flexural static strength of all the CFRP laminates depends remarkably on temperature and deflection rate. The master curves for the flexural static strength can be produced by using the modified reciprocation law of time and temperature. The time-temperature shift factors of the flexural static strength for the CFRP laminates were quantitatively in good agreement with the initial modulus of the respective matrix resins. The flexural fracture behavior for each of the three CFRP laminates can be divided into three different kinds of fracture modes: tensile fracture of fibers as the initiation of fracture in the short-time or low-temperature region; compression fracture of fibers in the medium-time or temperature region, and micro-buckling of fibers in the long-time or high-temperature region.