模拟转子叶片丢失后外传载荷影响特性研究

Effects of External Load on Simulated Rotor Blade Off Event

关键词:  航空发动机  叶片丢失  外传载荷  阻尼  动态响应

Key words:  Aero engine  Blade off event  External load  Damping  Dynamic response

摘要:

航空适航法则及相关安全性标准中均对航空发动机叶片丢失后的安全性设计提出了要求，为此需要明确关键零件在叶片丢失后所承受的载荷环境。本文利用Newmark-β法求解载荷传递系统的瞬态运动微分方程，得到振动响应与力载荷的关系。设计了模拟转子不平衡响应试验，进行突加不平衡质量后的转子响应测试，进而通过试验件内外振动响应获得了冲击载荷的传递规律。同时为研究阻尼在叶片丢失外传载荷中的影响效果，通过控制对试验件阻尼器是否供油，进行了有支点阻尼及无支点阻尼的振动响应对比试验。研究结果表明，冲击载荷在通过静子件后会产生明显衰减，本文试验对象传递比最高仅为53%，远离转子支承处所承受的载荷远低于转子支承处的载荷。同时，阻尼会明显降低冲击瞬间的外传载荷，但对转子稳定后的稳态载荷影响较小。本文研究表明：进行航空发动机叶片丢失条件下安全性分析时，需考虑冲击载荷的衰减及阻尼影响。另外，合理的阻尼器布局将有效降低叶片丢失时产生的冲击载荷作用，有助于提升发动机的抗冲击能力。

Abstract:

The aviation airworthiness law and related safety standards all set requirements for the safety design when aero engine blade off event happened， so it is necessary to clarify the load environment of key parts in the blade off event. In this paper， the Newmark-β method is used to solve the differential equation of transient motion of the load transfer system， and the relationship between vibration response and force load is obtained. A simulated rotor unbalance response test is designed， and the rotor response test after sudden unbalanced mass is carried out， and then the transmission law of shock load is obtained through the internal and external vibration response of the test piece. At the same time， in order to study the effects of damping on blade off of external load， a comparative test of vibration response with damping and without damping was carried out by controlling whether the damper of the test piece was supplied with oil. The results show that the shock load will be significantly attenuated after passing through the stator， the maximum transfer ratio of the tester in this paper is only 53%， and the load away from the rotor support is much lower than the load at the rotor support. At the same time， damping significantly reduces the external load at the moment of impact， but it has little effect on the steady-state load after the rotor is stabilized. Through the research of this paper， it is explained that the attenuation and damping effects of shock load should be considered when analyzing the safety of the aero engine in the blade off event. In addition， a reasonable damper layout will effectively reduce the shock load caused by the blade off event， which will help improving the impact resistance of the engine.