Carbon/Epoxy複合材料積層板のMode I層間破壊靭性に及ぼす温度と繊維配向角の影響

抄録

　　　Delamination is a predominant failure mechanism in composite structures. In the present study, double cantilever beam (DCB) tests were performed to investigate the effects of temperature and fiber orientation on the Mode I interlaminar fracture toughness, G_I, of carbon/epoxy composites, T800H/#3631. The values of G_I for three kinds of laminates, [0₁₂//0₁₂], [22.5/-22.5/0₈/-22.5/22.5//-22.5/22.5/0₈/22.5/-22.5] and [45/-45/0₈/-45/45//-45/45/0₈/45/-45], with a pre-cracked interface, that is // in each laminate, were obtained at various temperatures, i.e., -100°C, 20°C and 150°C. Fracture surface observation was also carried out by a scanning electron microscope (SEM) and optical microscope. It is shown that G_I is obviously affected by the temperature and fiber orientation. In the case of the specimen with delamination at 0//0, the fracture morphology changes as the delamination increases, but the value of fracture toughness for initiation G_IC (G_I at the crack initiation) is not so different from the one for propagation G_IR (G_I during the crack propagation), and the fracture toughness of the specimen with 0//0 interface is little affected by the temperature. However, G_IR of the specimen with 22.5//-22.5 interface shows a remarkable temperature dependence at a large crack length region. In case of the specimen with 45//-45 interface, G_IR is considerably affected by both failure mechanisms of crack jumping and fiber bridging, and the effect of temperature on G_IR is less than the case of the specimen with 22.5//-22.5 interface.