某型航空发动机压气机叶片振动疲劳寿命研究

Study on the vibration fatigue life for aero-engine compressor blade

以某型航空发动机压气机叶片为研究对象,在室温条件下进行了一阶弯曲振动疲劳试验,确定了叶片1×107循环基数下的振动疲劳极限。疲劳寿命分析表明在低振动应力下,Basquin方程可以很好地预测叶片的振动疲劳寿命。但在较高振动应力下,Basquin方程预测叶片的疲劳寿命偏于危险,原因在于Basquin方程不能反映塑性滑移对疲劳损伤的影响。为解决这一问题,引入了一个新的应变比因子对Basquin方程进行了修正。对于较高振动应力770MPa和740MPa下叶片的振动疲劳寿命而言,修正后的方程寿命预测误差分别为78.7%和38.5%。与原始Basquin方程相比,修正后的方程寿命预测精度分别提高了66.0%和19.2%。

The first-order resonance fatigue test for aero-engine compressor blade is conducted under room temperature.In the meantime,the vibration fatigue limit of the compressor blade corresponding to 1×107 cycles is determined in the fatigue test.Fatigue life analysis shows that the Basquin model predicts the vibration fatigue lives of the compressor blades well under the lower vibration stresses.However,under the higher vibration stresses,the predicted vibration fatigue lives of the compressor blades are unconservative by using the Basquin model since this model cannot reflect the effect of the plastic slide on the fatigue damage.To solve this problem,a new strain ratio factor is introduced in the Basquin model.Under the higher vibration stresses(770MPa and 740MPa),it is demonstrated that the error factors of the modified Basquin model are equal to 78.7% and 38.5%,respectively.In contrast to the original Basquin model,the life prediction error of the modified model improves about 66.0% and 19.2%,respectively.