考虑接触效应的拉杆转子非线性动力学特性分析

Nonlinear Dynamic Analysis of Rod-fastened Rotor Considering Contact Characteristic

本文建立了两盘拉杆式转子轴承系统动力学模型,模型受不平衡力和非线性油膜力激励,拉杆转子轮盘之间接触刚度由接触理论计算得到,采用4阶龙格库塔法进行求解,并使用分岔图和Poincare映射对比分析了不同的转速下,拉杆转子与单盘整体转子的非线性动特性的差异。通过研究得到以下结论:随着转速变化,相比于单盘整体式转子,考虑盘间接触效应的影响会使系统非线性动力学行为更加复杂,在中高转速范围内拉杆转子系统响应状态在周期运动与准周期运动或混沌运动状态之间出现多次反复,拉杆转子系统初次发生分岔的转速值变大,响应的幅值减小,在低转速范围内,盘间接触状态对系统状态影响较小,系统不受转速变化影响。

Nonlinear dynamic model of rod-fastened rotor bearing system was established and the model is considering the influence of unbalanced force and nonlinear oil film force. The contact stiffness between the disks of rod- fastened rotor is calculated by the reasonable contact theory. The nonlinear dynamic characteristics are investigated using fourth-order Runge- Kutta method. Bifurcation diagram and Poincare map are applied to discuss the difference of integral rotor and rod-fastened rotor bearing system dynamic characteristics at different rotating speed. The conclusions are as following: Compared to the integral rotor system, after considering the contact characteristic of disks, the system nonlinear dynamic will be more complex with the rotating speed increasing. In the higher speed region, rotor system state repeatedly appears between periodic motion, quasi periodic motion and chaotic motion. The first bifurcation speed value of rodfastened rotor system increases, and the magnitude of the response decreases. In the lower speed range, contact characteristic of disks has little effect on the state of the system, and the system is not affected by the speed change.