Fatigue Limit and Predication of Foreign Object Damage of TC4 Titanium Alloy

In order to study the effects of foreign object damage(FOD)on the high-cycle fatigue limit of aero-engine TC4 blade,the simulated blade was taken as the research object. The air gun method was used to simulate the foreign object damage of the leading edge of the blade under the impact of prefabricated steel balls under different working conditions. In order to obtain the fatigue limit of the damaged blades,the high-cycle fatigue test was carried out on the damaged blades. On this basis,the effects of notch residual stress distribution on the initiation of fatigue cracks and the fatigue limit were explored by finite element simulation. Finally,the fatigue limit of the blade was predicted by modifying the Peterson formula. The results show that the notch size caused by impact increases with the increase of impact energy. The high-cycle fatigue limit of the blades decrease with the increase of impact energy,and the notch depth has a great influence on the fatigue limit. The residual tensile stress at the bottom of notch may have some effect on the fatigue limit of blade. The error of Peterson formula in predicting the fatigue limit is large,and the error of prediction result after correction decreases from -30%~ 30% to -15%~15%. © 2023 Journal of Propulsion Technology. All rights reserved.