3-point flexural fatigue and Mode I interlaminar fracture tests were done to study the fatigue life and fracture toughness of nanoclay added carbon fiber epoxy composites. Fatigue life data was analyzed using Weibull distribution function, validated with Kolmogorov-Smirnov goodness-of-fit, and predicted by combined Weibull and Sigmoidal models, respectively. The nanophased samples showed more than 300% improvement in mean and predicted fatigue life. At 0.7 stress level, the nanophased samples passed the ‘run-out’ fatigue criteria (106 cycles), whereas, the neat samples failed much earlier. The interlaminar fracture toughness of nanophased samples was also enhanced significantly by 71% over neat samples. Optical and scanning electron microscopic images of the nanophased fractured samples revealed certain features that improved the respective fatigue and fracture properties of the composites.

中文翻译：

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纳米粘土增强碳纤维环氧复合材料的弯曲疲劳和断裂韧性行为

进行了3点弯曲疲劳和I型层间断裂试验，研究了纳米粘土添加碳纤维环氧复合材料的疲劳寿命和断裂韧性。疲劳寿命数据使用 Weibull 分布函数进行分析，使用 Kolmogorov-Smirnov 拟合优度进行验证，并分别通过结合 Weibull 和 Sigmoidal 模型进行预测。纳米相样品的平均疲劳寿命和预测疲劳寿命提高了 300% 以上。在 0.7 应力水平下，纳米相样品通过了“耗尽”疲劳标准（106 次循环），而纯样品则更早失效。纳米相样品的层间断裂韧性也比纯样品显着提高了 71%。