The influence of prior low‐cycle fatigue (LCF) on the residual fatigue life was investigated experimentally. A Ni‐based alloy was cyclically loaded under stress‐controlled low‐high (LH) block loading. In the first loading step, low‐amplitude loading was performed with the stress amplitude of 283.5MPa at 710°C. Different cycles of preloading were performed, varying from 100 to 10 000. Subsequently, high‐amplitude fatigue loading was carried out with the stress amplitude of 315MPa at 800°C. Experimental results show that the previous loading was beneficial to the residual fatigue life when the consumed life fraction is below 0.2 and detrimental when the consumed life fraction is larger than 0.2. A novel nonlinear fatigue damage accumulation model was proposed to estimate the residual LCF life under LH loading path considering the effects of load sequence and preloading cycles. The proposed model provided a better life prediction than some existing models, such as Kwofie‐Rahbar model, Miner' rule, Peng model, and Ye‐Wang model. Lastly, this model was further validated using various materials under LH and high‐low block loadings.

中文翻译：

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基于载荷历史的新型损伤累积模型的残余疲劳寿命预测

实验研究了先前的低周疲劳（LCF）对残余疲劳寿命的影响。镍基合金在应力控制的低-高（LH）块载荷下循环加载。在第一个加载步骤中，在710°C下以283.5MPa的应力振幅执行了低振幅加载。进行了不同的预加载周期，范围从100到10000。随后，在800°C的应力振幅为315MPa的条件下进行了高振幅疲劳加载。实验结果表明，当消耗寿命分数低于0.2时，先前的载荷有利于残余疲劳寿命，而当消耗寿命分数大于0.2时，则有利于残余疲劳寿命。提出了一种新的非线性疲劳损伤累积模型，该模型考虑了加载顺序和预加载周期的影响，估计了LH加载路径下的剩余LCF寿命。与某些现有模型（例如Kwofie-Rahbar模型，Miner规则，Peng模型和Ye-Wang模型）相比，该模型提供了更好的寿命预测。最后，在LH和高低块荷载下，使用各种材料进一步验证了该模型。