Nonlinear behavior and dynamic characteristics of multi-supported rotor systems under the influence of coaxiality deviation

Significant coaxiality deviation in a multi-supported rotor system can lead to large-amplitude whirling motion, severely affecting the system’s stability and performance. Studying the strong coupling characteristics induced by coaxiality deviation is crucial for ensuring the reliable operation of such systems. Therefore, this paper proposes a dynamic modeling method for multi-supported rotor systems. The rotor system is modeled using the finite element method and coupled with a discretized bearing model. Nonlinear vibration responses caused by coaxiality deviation are obtained through numerical integration. A comparative analysis of the influence of the bearings’ initial coaxiality and end face inclination angles on the system’s coaxiality deviation is conducted to accurately capture the vibration characteristics of the multi-supported system. Time-domain plots and frequency spectra are used to analyze the changes in vibration amplitude and coaxiality deviation under different rotational speeds, rotor eccentricities, and bearing clearances. Finally, the model is experimentally validated. The results indicate that large coaxiality deviation at the bearing positions increase bearing loads, and the unbalanced forces due to poor coaxiality alter the amplitude behavior of the rotor system before and after multiple critical speeds. This study provides valuable guidance for measuring and controlling coaxiality during the rotor assembly process in multi-supported systems.