In order to establish a prefabrication method for foreign object damage(FOD)of aeroengine blades that meets the require-ments of engineering development and evaluation,the influence of machining simulated FOD on the fatigue strength of titanium alloy blades was studied.Simulated TC4 blades with real engine blade leading edge features were designed and machined with three sizes of V-shaped notches to simulate FODs using two different precision wire EDM cutting processes.Under a stress ratio R=-1,the fatigue strengths of the notched simulated blades after 3×107 cycles were obtained by vibration fatigue tests based on the stepping method,and the relation-ship between the theoretical stress concentration factor(Kt)and the effective stress concentration factor(Kf)was established.The results show that the average fatigue strengths of the simulated blades with the same notch size under different machining precisions are basically the same,and the lower the machining precision,the worse the notch surface finish,and the greater the fatigue strength dispersion;the relationships of Kt and Kf is linear,the larger the Kt,the lower the fatigue strength,and the greater the Kf.The high-precision machining method can be used to simulate the influence of foreign object damage with a given Kt on fatigue strength through notch size.
关键词
外物损伤/机械加工方法/带前缘特征模拟叶片/疲劳强度/航空发动机
Key words
foreign object damage/machining method/simulated blade with leading edge feature/fatigue strength/aeroengine
维普
万方数据