基于临界距离理论的修复叶片疲劳极限评估

Foreign object damage is an important factor for the service of aeroengine fan and compressor blades. Small foreign object damaged notch can be typically repaired by machine or polish. To evaluate the fatigue properties of the machined and polished blades，the high-cycle fatigue strength of the machined and polished blades were tested，the fatigue limit prediction model was built based on the theory of critical distance， and compared with the classical Peterson model. The influence of different stress selection methods on the accuracy of the model was analyzed. The results showed that the model based on the theory of critical distance can accurately predict the fatigue limit of repaired notched blades，including a variety of repair processes，such as machined and hand polished. There is little difference between the prediction using the maximum absolute value of the principal stress and the normal stress along the blade length. The theory of critical distance model accuracy (average error less than 11%) is much higher than the classical Peterson's model (average error 26.03%).