キンク損傷を有するＰＢＯ繊維の疲労強度に及ぼす応力比の影響

抄録

In this study, the effect of stress rate on fatigue strength of PBO (Poly-p-Phenylene Benzobisoxazole) fiber with kinking damage was investigated in monofilament fatigue tests. High-modulus type PBO fiber (HM-PBO fiber) was used in the experiment. Kinking damages was created on surface of virgin fiber by winding bundle fibers to steel rod, set of 0.625 mm. Load-controlled fatigue tests were carried out using a sinusoidal load with frequency of 10 Hz and stress ratio of R = 0.1, 0.5 and 0.7, the load cell capacity was 10 N. Because the stress ratio can be adjusted between 0.1 and 0.7, it can be unambiguously arranged fatigue strength. The S - N curve of PBO fiber indicates kink damage with maximum stress at stress ratios of 0.5 and 0.7. In addition, the fatigue strength with a stress ratio of 0.1 is located on the lower strength side than the stress ratio of 0.5 or 0.7.