考虑几何特征与载荷敏感性的航空发动机结构件疲劳寿命预测模型

Prediction Model of Fatigue Life of Aeroengine Structural Parts Considering Geometric Features and Load Sensitivity

为了分析几何特征和载荷因素对几何复杂结构疲劳寿命预测的影响,给出了结构损伤区的定义方法,通过引入几何特征因子和疲劳权函数表征几何特征对疲劳寿命的影响,定义了载荷敏感性因数表征载荷因素对疲劳寿命的影响,以临界距离理论为基础,结合有限元分析、Origin函数拟合及Matlab程序等多种工具,发展了一种考虑结构几何特征与载荷敏感性的缺口疲劳寿命预测模型,并将该模型用于TC4、GH901和DZ125合金的缺口试样低循环疲劳寿命预测,结果表明:对于不同几何特征、不同载荷大小和不同材料等多种情况,寿命的预测值与试验值基本在2倍分散带之内,预测精度较为理想且高于多种现有其他方法,验证了该预测模型具有可行性和优越性。

In order to analyze the influence of geometric features and load factors on fatigue life prediction of geometric complex struc⁃tures,the definition method of structural damage zone was given.By introducing geometric features factors and fatigue weight functions to characterize the influence of geometric features on fatigue life,the influence of load sensitivity factors on fatigue life was defined.On the ba⁃sis of theory of critical distance(TCD),a notch fatigue life prediction model considering structural geometric features and load sensitivity was developed by combining finite element analysis,Origin function fitting and Matlab program.The model was used to predict the low cy⁃cle fatigue life of notch samples of alloys of TC4、GH901 and DZ125.The results show that the predicted value and the test value of life are within 2 times of the dispersion zone for different geometric features,load sizes and materials.The prediction accuracy is ideal and higher than other existing methods,which proves the feasibility and superiority of the prediction model.