低频大摆幅基础运动对滑动轴承-转子系统动力学特性的影响

考虑了低频大摆幅基础运动及转子在轴瓦内倾斜而产生的非线性油膜力矩等因素,基于拉格朗日方程建立了滑动轴承-转子系统的动力学模型。采用数值方法研究了基础运动对该系统非线性动力学特性的影响。结果表明:转子系统第一次失稳后其动力学分岔特性出现复杂的上下两支拟周期运动,并且第二次出现失稳的转速有所提高;在转子转速较高时,转子的振幅急剧增大,且在拟周期阶段就已经碰触轴瓦内壁而未能过渡到混沌状态。最后讨论了基础运动的摆动频率和幅值变化对系统动力学特性的影响。上述结论有助于认识低频大摆幅基础运动下滑动轴承-转子系统的运动规律。

Effects of low frequency and large swing base motion on dynamic characteristics of sliding bearing-rotor system

Considering factors,such as,base motion with low frequency and large swing and nonlinear oil film moments caused by tilting of rotor in bearings,the dynamic model of a sliding bearing-rotor system was established using Lagrange equation.Then,effects of base motion on nonlinear dynamic characteristics of the system were studied using the numerical method.The results showed that after the rotor system loses its stability for the first time,its dynamic bifurcation characteristics have two-branch of upper and lower complex quasi-periodic motions,and the rotating speed during the system losing its stability for the second time rises;when the rotor speed is higher,the rotor’s vibration amplitude increases sharply,and it reaches inner wall of bearing bush in quasi-periodic stage and can’t transit to chaotic state;effects of swing frequency and amplitude variation of base motion on dynamic characteristics of the system were discussed;the above conclusions are helpful to understand motion laws of sliding bearing-rotor systems with low frequency and large swing base motion.