基于不同临界法预测曲轴疲劳极限载荷

Crankshaft Fatigue Limit Load Prediction Based on Different Critical Distance Methods

以多款发动机的曲轴为研究对象,基于临界理论的不同方法并利用有限元法计算曲轴在弯矩载荷作用下应力集中处的应力分布并求解等效应力。通过这种等效处理,将预测曲轴的疲劳极限问题转化为求解应力集中处的等效应力问题,并结合已有的曲轴疲劳强度试验数据,对不同临界距离方法在工程实际应用中的适用性做出评价。研究结果表明:基于临界距离法可以准确预测不同圆角结构的曲轴的疲劳极限载荷,而基于临界点法在预测相同圆角结构的曲轴时具有较高的精度,但是在预测不同结构的曲轴的疲劳极限载荷时误差较大。

Different critical distance methods and finite element method were used to calculate the equivalent stress in the stress concentration area of several kinds of crankshafts under bending load. By this, treament, the prediction of the crankshaft fatigue limit load was converted to solving the problem of the equivalent stress in the stress concentration area, and together with the experimental data, the applicability of the critical distance methods in engineering practice was evaluated. Results show that the critical distance method can be used to accurately predict the fatigue limit load of crankshafts with different fillet structures, while the critical point method can predict the fatigue limit load of crankshafts with the same fillet structure, but it has a great error in predicting the crankshafts with different fillet structure.