中文摘要：

针对传统圆棒试样扭转低周疲劳存在的问题,采用漏斗形试样对材料C2 5 0马氏体钢（C r强化）进行4 种温 度（20, 150,200,350℃） 、 两种应变幅比（-1、 0.1）下的扭转低周疲劳试验, 得到-系列S-N 曲线.对比分析ManSon- Coffin模型、拉伸滞后能损伤模型以及三参数幂函数模型3种低周疲劳寿命预测模型,评述其基本假设、应用范围和 特点.应用3种模型分别对上述8种工况的试验结果进行寿命预测对比分析,并对比分析温度对扭转低周疲劳寿命 的影响.结果显示：三参数幂函数公式能更好地拟合试验结果,明显克服另外两种预测模型的缺陷.因此,对于扭转低 周疲劳寿命的预测宜采用三参数幂函数模型,其预测结果更接近真实值.

英文摘要：

To solve the problem of torsional low cycle fatigue in traditional round bar specimens, the funnel-type specimens of C250 maraging steel were adopted for the torsional low cycle fatigue test under four kinds of temperature （20,150,200,350℃）and two kinds of strain amplitude ratio （-1 ＆ 0.1）. Based on tests, a series of S-N curves were obtained. Comparing with Manson-Coffin model, stretching hysteresis energy damage model and three -parameters power model, characteristics and application scope of different prediction methods were summarized in the present study. Eight kinds of test conditions were compared by using of the above three kinds of models. Then, the effects of temperature to torsional low cycle fatigue life were discussed. Results show that three -parameters power model can better fitting the test results, the prediction model can remove the disadvantages of the other two kinds of prediction models obviously. Therefore, it is appropriate that the torsional low cycle fatigue life prediction using three -parameters power model and the prediction more accurately.