During an aeroengine test,there occurred a bistable vibration phenomenon consisting of a high-amplitude vibration abnormal mode and a low-amplitude vibration normal mode at the same physical speed.To address this issue,unbalance sensitivity tests of the core engine rotor under whole engine state were conducted.By adjusting the unbalanced state of the core rotor through small-scale local disassembly,the vibration responses of the engine bearing seat under various balanced states were obtained,and the sensitivity of the whole-engine vibration to the unbalance of the core rotor was analyzed.The results show that in various unbalanced states,the vibration phases of the abnormal vibration mode converge to the same angle,and the unbalance causing the abnormal vibration mode occurs within a fixed angular range.The phase lag angle of the bearing seat measuring point ranges from 120° to 150° under high-speed abnormal vibra-tion mode.Adding counterweights at the angular position to the opposite side of the unbalance causing the abnormal vibration mode of the core engine can successfully eliminate the abnormal vibration mode and solve the bistability problem.It has been verified on multiple engines of the same model,and the balance accuracy exceeds 80%.
万方数据
维普
