压气机转子叶片掉块故障研究

Fracture fault of the compressor rotor blade

针对航空发动机压气机第5级转子叶片掉块故障,通过理化分析、振动特性分析及试验验证,对故障叶片掉块性质和产生原因进行了梳理。结果表明,叶片掉块性质为高周疲劳断裂,裂纹起始于叶尖与叶盆或叶背的交角处。主要原因是叶片存在设计缺陷,在发动机工作常用转速4700 r/min、4900 r/min附近存在高阶振动点,即8阶、9阶振动模态在激振力倍频80下可能引起共振。根据分析结果,采取优化叶型措施进行改进。经外场使用验证,改进效果良好,排除了故障。

Aiming at the fracture of the 5th stage rotor blade of an engine compressor,the property and cause were analyzed by means of crystal phase analysis,vibration characteristic analysis,test verification,etc.The results show that the failure character of the crack is high cycle fatigue,and the crack starts at the angle between the blade tip and concave or the convex.The main reason is that the blade design is insuffi⁃cient.There are high-order composite vibration points near the engine operating speed of 4700r/min and 4900r/min,that is to say,the eighth and ninth order vibration modes under the frequency doubling of 80 ex⁃citation force might lead to resonance.According to the analysis results,the blade shape is optimized with obvious effect and the fault is cleared after field validation.