| Abstract: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 3×10 7 cycles were obtained by vibration fatigue tests based on the stepping method, and the relation?
ship between the theoretical stress concentration factor (K t ) 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 K t and K f is linear, the larger the K t ,the lower the fatigue strength, and the greater the K f .The high-precision machining
method can be used to simulate the influence of foreign object damage with a given K t on fatigue strength through notch size. |
