Vibrations of a rigid-flexible coupled dual-rotor system under misalignment fault

In this paper, a novel coupled vibration and transmission characteristics study method for dual-rotor system with misaligned fulcrums based on the multi-body dynamic is proposed from the perspective of vibration mechanics. First, an analytical model of the dual-rotor system considering the misalignment of the fulcrum is deduced based on the rigid-flexible coupling dynamic model of a dual-rotor system. Second, the vibration characteristics of the dual-rotor system with misalignment faults are investigated, and the effects of misalignment magnitude, unbalanced vector, rotational speed, and additional torque on vibration are discussed. The main factors affecting vibration were analyzed, and the influence of misalignment faults on the transmission law of unbalanced vibration between high-pressure and low-pressure rotors was explored. After that, a rigid-flexible coupling multi-body dynamics simulation model of the dual-rotor system considering the misalignment of fulcrums was established based on the multi-body dynamics simulation platform. The theoretical results were verified by simulation analysis. Finally, the characteristics and laws of coupled vibration of the dual-rotor system under misalignment faults are studied, and the influence of misalignment excitation at different positions on the motion form and main frequency of the dual-rotor system m is revealed.