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.