基于塑性应变能的涡轮盘多轴疲劳寿命预测方法

在分析疲劳裂纹产生机理的基础上,将塑性应变能和临界平面结合起来,同时引入剪应变能比例因子,提出一种新的多轴损伤参量,通过试棒单轴低循环疲劳试验应力应变曲线得到总的塑性应变能,进而得到一种新的多轴疲劳寿命预测模型。通过对比分析,得到了最佳剪应变能比例因子。使用该模型、Chen-Xu-Huang(CXH)模型、Liu-Wang(LW)模型对某型发动机涡轮盘销钉孔低循环疲劳寿命进行预测,并与真盘试验结果进行对比。结果表明,该多轴疲劳寿命预测模型预测误差为20.5%,优于CXH和LW模型。

Predicting Multiaxial Fatigue Life of Turbine Disk with Plastic Strain Energy

Based on the fatigue crack generation mechanism,we propose a new multiaxial damage parameter by integrating plastic strain energy with critical plane and introducing the shear strain energy proportion factor.Then we establish the multiaxial fatigue life prediction model by using the total plastic strain energy obtained with the stress-strain curve from the uniaxial specimen low cycle fatigue test.The optimal shear strain energy factor was obtained with comparative analysis.The low cycle fatigue life of a turbine disk was predicted by using the Chen-Xu-Huang(CXH) and Liu-Wang(LW) model.The prediction results were compared with the experimental results on the fatigue life of a real turbine disk,and the comparison results show that the prediction error of our model is 20.5%,lower than that of the CXH and LW model.