压气机转子叶片掉块断裂分析

Fracture Analysis on Compressor Rotor Blades

某型发动机外场服役中多次出现压气机转子叶片叶尖掉块断裂故障,通过掉块叶片表面形貌观察、断口分析、硬度检测、金相检验、多起失效件的类比分析以及叶片振动模态分析,对叶片掉块断裂原因进行了分析。结果表明:所有压气机转子叶片掉块断裂模式相同,均属振动疲劳断裂掉块;叶片在发动机工作转速范围内存在高阶复合振动点,引起叶片共振是导致其振动疲劳断裂掉块的主要原因;叶片与机匣摩擦导致叶尖局部过烧或形成摩擦热应力裂纹促进了疲劳裂纹的萌生。最后针对叶片掉块断裂原因提出了相应的解决措施。

The compressor rotor blades of a certain engine frequently fractured at the blade tip in the field service, and the fracture reasons were analyzed by means of blade surface morphology observation, fracture analysis, hardness testing, metallurgical examination, analogy analysis of many failure parts, and blade vibration model analysis. The results show that all the rotor blades of the compressor had the same fracture mode which was vibration fatigue fraeture. Within the engine operating speed range, the blades had high order composite vibration points which induced resonance of the blades, and that was the main reason for the vibration fatigue fracture. The local burning or friction heat stress cracks induced by the friction between the blade tip and the casing promoted the initiation of fatigue cracks. Finally, the corresponding solutions for fracture reasons of the blades were proposed.