極微少量のガラス短繊維を含む非結晶性高分子材料の疲労破壊に及ぼす温度の影響

抄録

In order to know the fatigue fracture mechanism of FRP, quasi-static tensile and fatigue tests were performed at various temperatures using AS and PC samples with small content of short glass fibers, which were fabricated by injection molding. The following results were obtained. In tensile fracture, (1) for AS, the crazes initiated at the end of glass fibers parallel to the loading direction caused a final fracture, while at -192°C, fracture started at the crazes formed on the surfaces of the test sample, and (2) for PC, either of diamond shaped cracks and debonding initiated around the fibers initiated the tensile fracture, while at -192°C, tensile fracture occurred due to the surface crazes. In fatigue fracture, (3) for AS, the formation of crazes at the ends of glass fibers became the initiation site of fatigue fracture at the temperature range tested here and (4) for PC, under a relatively high stress amplitude at 25°C, crack growth from the shear cracks initiated around the fibers perpendicular to the loading direction caused fatigue fracture, but at relatively low temperatures, the surface crazes led to a final fracture.