スタンパブル炭素繊維強化ナイロン複合材料の疲労強度とその応力比依存性

抄録

The static and fatigue behaviors of stampable discontinuous carbon fiber-reinforced polyamide (DCF/PA) composite have been examined. Static tension and compression tests are first performed at different temperatures (RT, 70°C and 130°C), respectively, to quantify the temperature dependence of basic mechanical properties of the composite. Then, constant amplitude fatigue tests are carried out for different stress ratios (0.1, χ, -1 and 10) at different temperatures (RT, 70°C and 130°C), respectively. The fatigue test results demonstrate that the S-N relationship of the discontinuous fiber composite significantly depends on stress ratio, and fatigue degradation occurs most rapidly at the critical stress ratio in line with the observations made thus far for continuous carbon fiber composites. Finally, the anisomorphic constant fatigue life diagram approach developed for continuous carbon fiber composites is applied to the DCF/PA composite, and it is proved that this method can successfully be used to predict the fatigue life values of the discontinuous carbon fiber-reinforced composite at different stress ratios as well.