含损伤不锈钢叶片剩余疲劳极限研究

Research on the residual fatigue limit of damaged stainless-steel blades

摘要:

航空发动机叶片在遭受外物冲击时，其叶片损伤可能导致疲劳断裂，对发动机的可靠性和服役安全构成了严重威胁。为了研究金属外物损伤对航空发动机叶片疲劳性能的影响规律，采用高速轻气炮试验系统将直径为 3 mm 的钢珠加速至 290~310 m/s，对叶片进行外物损伤预制试验；基于高周振动疲劳试验系统，探讨金属外物损伤对不锈钢叶片剩余疲劳极限的影响；通过分析缺口尺寸对疲劳极限的作用规律，结合 Peterson 模型，预测含损伤叶片的疲劳极限。结果表明：含损伤叶片的剩余疲劳极限随着损伤深度和宽度的增加而显著下降，且缺口深度对疲劳极限的影响最为显著；根据 Peterson 模型的预测，损伤叶片的剩余疲劳极限在 1.5 倍分散带内，且大多数试验值均低于预测值。

Abstract:

When aero-engine blades are subjected to foreign object impact, the resulting blade damage may lead to fatigue fractures, which pose a serious threat to the reliability and operational safety of the engine. In order to investigate the effect of metallic foreign object damage (FOD) on the fatigue performance of aircraft engine blades, a high-speed light gas gun testing system was used to accelerate 3mm-diameter steel balls to speeds of 290–310 m/s for the pre-damage testing of the blades. Subsequently, a high-cycle vibration fatigue testing system was used to study the impact of metallic foreign object damage on the residual fatigue limit of stainless-steel blades. By analyzing the influence of notch size on the fatigue limit and using the Peterson model, the fatigue limit of the damaged blades was predicted. The results show that the residual fatigue limit of the damaged blades decreases significantly with increasing damage depth and width, with the notch depth having the most pronounced effect on the fatigue limit. According to the predictions from the Peterson model, the residual fatigue limit of the damaged blades falls within 1.5 times the scatter band, and most experimental values are lower than the predicted values.