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研究了受横向不平衡电磁激励的转子-轴承系统的非线性振动响应。首先将转子-轴承系统简化为带有质量不平衡并受横向激励的连续梁,由于短轴承的油膜力和电磁力的共同激励,系统振动具有强非线性特性。用Galerkin方法把偏微分控制方程离散为常微分方程组,采用四阶Runge-Kutta法对该系统进行数值仿真研究。其次比较了转轴分别在电磁力、油膜力单独作用和两种力共同作用下的振动特性,研究表明电磁力和油膜力对转子系统的非线性振动和分岔有着不同的贡献:油膜力的存在抑制了拟周期运动的发生,延长了稳定运行区域;电磁力拉长了拟周期发生的区域,降低了转子系统发生突发性破坏的风险。最后给出了系统响应随转速、电磁参数、油膜粘度等控制参数变化的分岔图,表明:系统在两个方向的运动随控制参数的变化趋势基本相同,经历了周期、倍周期、拟周期等非线性运动交替出现的过程;且油膜粘度的增大有利于转子系统的安全运行。
The nonlinear vibration response of a rotor-bearing system excited by lateral unbalance electromagnetic excitation is studied. Firstly, the rotor-bearing system is simplified as a continuous beam with unbalanced mass and lateral excitation. Due to the co-excitation of the oil film force and the electromagnetic force of the short bearing, the system vibration has strong non-linearity. The Galerkin method is used to discretize the partial differential governing equations into the system of ordinary differential equations. The fourth-order Runge-Kutta method is used to simulate the system. Secondly, the vibration characteristics of the rotating shaft under the action of electromagnetic force and oil film force alone and two kinds of force are compared respectively. The results show that the electromagnetic force and oil film force have different contributions to the nonlinear vibration and bifurcation of the rotor system: the existence of the oil film force It suppresses the occurrence of quasi-periodic motion and prolongs the stable operation area. Electromagnetic force lengthens the quasi-periodic area and reduces the risk of sudden damage to the rotor system. Finally, the bifurcation diagrams of the response of the system to the control parameters such as rotation speed, electromagnetic parameters and oil film viscosity are given. The results show that the movement of the system in two directions is basically the same with the change of the control parameters, and undergoes the cycle, the doubling period and the quasi-period And other non-linear alternating motion of the process; and oil film viscosity is conducive to the safe operation of the rotor system.