成形温度と板厚が熱硬化CFRP円筒部材の衝撃エネルギー吸収特性に及ぼす影響

抄録

In recent automobile developments, the compatibility between a lighter vehicle body for lower fuel consumption and high clash safety performance has been an essential requirement. It is necessary to increase the energy absorption (EA) efficiency of car body frames, for which the continuous brittle destruction phenomenon of carbon fiber reinforced plastics (CFRP) pipes can be effectively utilized. In this paper, we addressed the effect of curing temperature and thickness on the process-induced residual stress and the destruction behavior under clashing. We measured the residual stress, residual strain, and EA characteristics of CFRP pipes cured at 80ºC, 100ºC, and 130ºC. Fiber Bragg grating (FBG) sensors were embedded into the specimens during the lay-up process to measure the cure strain and residual stress. We used a drop impact test for the evaluation of EA characteristics. The results confirmed that with increasing curing temperature, both, the residual stress in the in-plane direction and the EA amount increased, because of the suppression of fiber breakage in the hoop direction. In contrast, with increasing thickness, the residual stress in the out-of-plane direction increased, while the EA efficiency decreased due to increased interlaminar fracturing. The insight gained is useful for designing appropriate cure cycles for CFRP pipes with high EA efficiency.