摘要: |
高阶模态对高周疲劳失效有很大影响,但对高阶模态下的离心叶轮振动特性研究较少。本研究建立某型离心叶轮有限元模型,并通过测频试验验证了模型的准确性;开展离心叶轮高阶振动特性分析,获得了危险点位置;开展了试车试验,分析叶轮裂纹特性,验证危险点位置预测方法的合理性。结果如下:离心叶轮主1阶固有频率仿真计算结果与试验结果的误差仅为1.2%;叶轮相对应力最大值位于排气边主叶片叶根处,此处即为共振疲劳危险点;叶轮裂纹性质为高周疲劳裂纹,裂纹起源于排气边叶根处,与有限元分析结果一致,证明了使用共振频下的振动应力预测其共振疲劳危险点的合理性。本研究的结论可以为离心叶轮的设计和改进提供理论基础和技术支持。 |
关键词: 离心叶轮;高阶模态;疲劳裂纹;共振;危险点预测 |
基金项目: |
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Prediction of Minimum Life Point of Resonance Fatigue and Experimental Verification of the Centrifugal Impeller收稿日期:2024-01-26 |
Li Weichao Wu Wei
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AECC Nanjing Light Aero-engine Co., Ltd., Nanjing 211100
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Abstract: |
Higher-order modes have a great influence on high-period fatigue failure, but there are few previous studies on the vibration characteristics of centrifugal impellers in higher-order modes. In this study, a finite element model of the centrifugal impeller is established, and the accuracy of the model is verified by frequency measurement test. Then the centrifugal impeller high-order vibration characterization is carried out to obtain the location of the minimum life point. Finally, the trial test is carried out to analyze the characteristics of the impeller crack and verify the reasonableness of the method for determining the location of the danger point. The results show that the error between the simulated and tested results of the main 1st order intrinsic frequency of the centrifugal impeller is only 1.2%. The maximum relative stress of the impeller is located at the root of the main blade on the exhaust side, where is the danger point of resonance fatigue. The nature of the impeller crack is high-frequency fatigue crack, and the crack originates at the root of the exhaust side leaf, which is consistent with the finite element analysis results. The test results justify the use of vibration stress at resonance frequency to predict its resonance fatigue minimum life point. The conclusions of this study can provide theoretical basis and technical support for the design and improvement of centrifugal impeller. |
Key words: centrifugal impeller;higher order modes;fatigue cracking;resonance;prediction of minimum life point |