多自由度转子-轴承系统周期运动分岔及稳定性研究

建立考虑诸多因素的转子-轴承系统多自由度模型,将与Newmark结合的打靶法应用到多自由度转子-轴承系统的周期稳定性分析中。着重研究了转子-轴承系统失稳转速随系统偏心量、轴承间隙、润滑油动力粘度以及轴承长径比的变化规律,研究结果表明:提高系统偏心量、减小轴承间隙、增大润滑油动力粘度以及选择适当的轴承长径比均能提高转子-轴承系统的失稳转速;对于不同的参数值,系统表现出不同的分岔规律,系统发生半速涡动时表现为倍周期分岔或拟周期分岔,发生油膜振荡时则表现为拟周期分岔。

Bifurcation and stability of the flexible rotor-bearing system by a continuum model

A nonlinear continuum model of the flexible rotor-bearing system is established with some important factors being considered,the bifurcation and stability of the periodic motions of system are studied by using the continuation-shooting algorithm combined with the Newmark method.This paper focuses on that the instability speed changes with the eccentricity of the rotor,the clearance of the bearing,the oil viscidity of the bearing and the length-to-diameter ratio,of the bearing.The results show that the stability may be improved by increasing the eccentricity of the rotor,reducing the clearance of the bearing,increasing the oil viscidity and choosing an appropriate length-to-diameter ratio of the bearings.Furthermore,the different kinds of bifurcation appear with different parameters.The half speed swirling occurs through the period-doubling and the quasi-period bifurcation,and the oil whip phenomenon appeared through the quasi-period motion.The conclusions have provided a theoretical reference for vibration control and stability design of the more complex rotor-bearing system.