裂纹对航空发动机整体叶盘振动特性的影响

Effect of Cracks on the Vibration Characteristics of Aero-Engine Integral Impeller

针对航空发动机涡轮叶盘运行中产生的疲劳裂纹改变振动特性的问题,基于有限元模态分析理论对其进行研究。建立不同裂纹长度、裂纹分布位置的整体叶盘有限元模型,分别分析动静态下固有频率的变化;分析裂纹对整体叶盘频率转向的影响;最后,通过分析含裂纹叶片在激励作用下的响应,得出其响应幅值和振动方向的变化。结果表明:裂纹会降低整体叶盘固有频率,且对低阶频率影响较大;裂纹会影响整体叶盘振型,出现振动局部化现象;裂纹的出现影响整体叶盘频率转向现象的发生;整体叶盘中含裂纹叶片的响应峰值随着裂纹长度的增加而逐渐增大,且裂纹叶片会出现大范围振动反向现象。

In order to solve the problem of vibration characteristics changing due to fatigue cracks generated during the operation of the aero-engine turbine impeller,it was studied based on the finite element mode analysis theory.The finite element model of the integral impeller with different crack lengths and crack distribution locations was established to analyze the natural frequency changes under dynamic and static conditions respectively.The influence of the crack on the frequency steering of the integral impeller was analyzed.Finally,by analyzing the response of the cracked blade under excitation,the variation of its response amplitude and vibration direction was obtained.The results show that the crack reduces the natural frequency of the integral impeller and has a great effect on the low order frequency.The crack can affect the vibration mode of the integral impeller,and the vibration localization phenomenon appears.The appearance of cracks affects the frequency steering of the integral impeller.With the increase of crack length,the response peak value of the cracked blade in the integral impeller increases gradually,and the cracked blade has a wide range of reverse vibration phenomenon.