突加不平衡下发动机振动响应分析

为了研究发动机的突加不平衡故障，建立了航空发动机低压转子模型，完成了转子实验器的模态校核。在此基础上对突加不平衡下实验器的转子件响应进行了理论分析与实验对比。进一步建立了转子-支承-机匣分析模型，完成了响应的分析与实验结果对比。结果表明:建立的转子-支承-机匣模型考虑了发动机实际运转过程中的角加速度项和挤压油膜阻尼器瞬态项，分析结果与实验结果相符，突加不平衡位置处振动位移响应的分析结果与实测结果之间的相对误差为2.1%。在校核转子件响应后，将转子件载荷作为支承-机匣模型的载荷输入，考虑发动机结构特征，建立支承-机匣模型进行响应分析，分析结果与实验结果基本一致，对于靠近突加不平衡位置的振动速度响应，其分析结果与实测结果之间的相对误差不超过4.7%。分析结果能够体现突加不平衡后转子响应的冲击特征和转子-支承-机匣响应层层减弱的过程，所建立的计算方法具有较好的推广性。 

Analysis of aero-engine vibration response under sudden unbalance

In order to study the sudden unbalance fault of engine，a low-pressure rotor model of aero-engine was established，and mode check was finished.On this basis，comparison between analysis and test results of the rotor response of test rig under sudden unbalance was conducted.Then analysis model of the rotor-support-case was established，and comparison between analysis and test results was finished.Result showed that，the angular acceleration term and the transient term of the squeeze film damper，which exist during the actual operation of engine，were taken into account when establishing the rotor-support-case model，and the analysis results were in agreement with the test results.The relative error between analysis result and test result of vibration displacement response at sudden unbalance position was 2.1%.After checking the responses of the rotor，the support-case model was established for response analysis，taking the load of rotor parts as the input of the support-case model and considering the characteristics of engine structure.The analysis results were consistent with the test results，with the relative errors between analysis and test results of vibration velocity response near sudden unbalance position no more than 4.7%.The analysis results show the shock characteristics of rotor response after sudden unbalance and the layer attenuation of rotor-support-case response.The calculation method established has good prospect for promotion.