疲劳-蠕变交互作用的寿命预测探讨

Discussion of life prediction for fatigue-creep interaction

从反映物系运动过程的能量守恒定律和动量守恒定律出发,对材料疲劳-蠕变交互作用下的破坏过程进行了分析,推导出一个新的疲劳-蠕变交互作用的寿命预测模型.与已有的疲劳-蠕变交互作用寿命预测模型相比,本文提出的模型具有适用性强(对于应力控制模式和应变控制模式均适用)、形式简单、所需参数少和应用方便等优点.为检验本文提出模型的准确性,进行了1.25Cr0.5Mo钢光滑试样540℃和520℃环境下应力控制的梯形波加载试验,用本文提出的模型进行了上述两种温度环境下的疲劳-蠕变交互作用的寿命预测,预测结果与实际测量结果符合较好.

A new model for the life prediction of fatigue-creep interaction has been developed in this paper. In this model, the law of energy conservation and the momentum conservation principle are used to describe the process of fatigue-creep interaction. The change of internal energy is a key parameter concerned with the life. It should be pointed out that the new model mentioned above is applicable to the life prediction of strain-controlled tests and stress-controlled tests. Owing to only several parameters in the expression of this model, it is very easy to use this model to predict the life of fatigue-creep interaction. To check the validity of the new model proposed in this paper, the assessments for the fatigue-creep interaction tests of 1.25Cr0.5Mo steel under stress control of trapezium waveforms at 540 ℃ and 520 ℃ have been performed by this new model. A good agreement is found between the predicted results and the experimental data.