航空发动机转子叶片的声振疲劳特性试验

Experiment on acoustic vibration fatigue properties of the aero-engine rotor blade

由于振动载荷、声载荷等会造成航空发动机转子叶片的高周疲劳失效,通过试验研究了发动机转子叶片的声振疲劳特性.首先研究了叶根边界条件对发动机转子叶片声响应特性的影响,对3组叶片施加不同的顶紧力,由低到高施加声载荷,试验得到不同叶根边界条件下叶片的声响应与声载荷的关系,并且得出叶根边界条件对转子叶片声响应大小有影响的结论.随后研究了叶片的声振疲劳特性,得出以下结论:声载荷作用下,叶片确实可以发生破坏.在两种不同的激励方式(随机振动激励与正弦振动激励)作用下叶片的频率下降略有不同,并且在动应力水平相同的条件下,发动机转子叶片在正弦振动激励下的寿命远大于其在随机振动激励下的寿命.

Vibration load, sound load and other factors may result in high cycle fatigue of aero-engine rotor blade. The acoustic vibration fatigue properties of aero-engine rotor blades were studied experimentally. Firstly, the effects of blade root boundary conditions on the acoustic responsiveness properties of aero-engine rotor blade were studied. Three differ- ent clamping forces were applied to three groups of rotor blades. Then sound loads were ap- plied to each group of blades from low to high. The relationship between the acoustic re-sponsiveness and the sound pressure under different boundary conditions was therefore got. The results showed that blade root boundary condition was an important influential factor to the blade acoustic responsiveness. Then the acoustic vibration fatigue properties of the blade were studied. Conclusions could be drawn as follows： rotor blade could be damaged under sound loads; blade frequency decrease is slightly different when applying two different vibration excitations to two rotor blades, i.e. random vibration and sinusoidal vibration. The lifespan of blade under sinusoidal excitation is much longer than under random excitation if both are at the same dynamic stress level.