基于顺序雨流法和临界平面法的多轴变幅低周疲劳寿命评价

 在多轴变幅疲劳寿命预测过程中，合适的雨流计数法对复杂加载历程分析非常重要，但是大多数雨流计数过程往往无法保持原始的加载顺序特性，进而会导致非保守的疲劳损伤和寿命预测．本文提出一种考虑加载顺序效应并基于临界面概念的多轴实时顺序雨流法，该方法既具有实时顺序计数特点，同时与Bannantine-Socie多轴雨流法结合，可以实现对主要通道内的载荷历程实时的雨流计数．基于Morrow 模型，提出一种新的考虑加载顺序的线性损伤累积方法．相对于传统雨流计数法需要得到完整的载荷数据后才能进行分析的特点，新方法计算效率更高，实用性更强．通过对316L 不锈钢的多轴疲劳试验数据的分析，验证了该方法在多轴疲劳寿命预测过程中的有效性．

Life Evaluation of Multiaxial Variable Amplitude Low-Cycle Fatigue Based on Sequential Rainflow Method and Critical Plane Method

 In process of multiaxial variable amplitude fatigue life prediction, an appropriate rainflow counting method is important for analysis of a complex loading process. But most rainflow counting processes can’t maintain original loading sequence, which will lead to non-conservative fatigue damage and life prediction. A multiaxial real-time sequential rainflow method based on critical plane is proposed to consider loading sequence effect. The real-time sequential counting method combines with Bannantine-Socie multiaxial rainflow method to realize a real-time rainflow count of loading history in the main channel. Based on the Morrow model, a new linear damage accumulation method is proposed to reflect the loading sequence effect. Compared with the traditional rainflow counting method, the new method is more efficient and practical. The efficiency of the proposed method is validated by reasonable correlations with the experimental data of 316L steel tubular specimens subjected to various multiaxial fatigue loadings.