Shen Zhibin, Cai Zhihui, Wang Hong, Xu Bo, Zhang Linye, Song Yuxuan, Gao Zengliang
Wenzhou Special Equipment Inspection & Science Research Institute, Wenzhou 325000, China.
Huzhou Special Equipment Inspection Center, Huzhou 313099, China.
Materials (Basel). 2025 Jul 11;18(14):3274. doi: 10.3390/ma18143274.
The accumulation of fatigue damage is primarily caused by cyclic plastic deformation. In low-cycle fatigue, cyclic plastic deformation is the dominant deformation mode. In high-cycle fatigue, although most deformation is elastic, plastic deformation may still occur in localized regions of stress concentration and plays a critical role in the initiation of fatigue cracks. Considering that cyclic plastic deformation can be characterized by hysteresis loops, this study modifies the flow stress equation and the cyclic plastic deformation relationship based on stress-strain hysteresis loops at half-life cycles under different strain amplitudes. An improved model for life prediction that incorporates the effects of strain amplitude is proposed. The results of experiments on 310S stainless steel and 1045 carbon steel demonstrate that the model achieved prediction errors within a factor of two and provided reliable predictions for both high-cycle and low-cycle fatigue life across the entire ε-N curve.
疲劳损伤的累积主要由循环塑性变形引起。在低周疲劳中，循环塑性变形是主要的变形模式。在高周疲劳中，尽管大部分变形是弹性的，但塑性变形仍可能发生在应力集中的局部区域，并在疲劳裂纹的萌生中起关键作用。考虑到循环塑性变形可以用滞后回线来表征，本研究基于不同应变幅值下半寿命周期的应力-应变滞后回线，修正了流动应力方程和循环塑性变形关系。提出了一个考虑应变幅值影响的改进寿命预测模型。对310S不锈钢和1045碳钢的实验结果表明，该模型的预测误差在两倍以内，并且在整个ε-N曲线上对高周和低周疲劳寿命都提供了可靠的预测。
