关键词: 双转子系统;随机激励;虚拟激励法;响应

Abstract: Aero-engine dual-rotor system is subject to unpredictable excitation, resulting in the random vibration. In order to study this phenomenon, the motion equation of the unbalanced dual-rotor system subjected to random excitation is established. Using pseudo-excitation method, the power spectral density (PSD) of displacement of the dual-rotor system subjected to random excitation is calculated, and the dynamic characteristics of the structure are studied. The researches show that with the increasing of the stiffness coefficient of the intershaft bearing, the natural frequency of the system increases and tend to a constant value. At the same time, the peak of the PSD of displacement caused by external random force decreases and tends to an infinitesimal, while the peak of the PSD of displacement caused by the system coupling effect increases to a peak, then decreases and tends to an infinitesimal after a certain stiffness. From the research, some measures are made for protecting dual-rotor aircraft engines from random vibration. 

Key words: Dual-rotor system; Random excitation; Pseudo-excitation method; Response