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Abstract: A nonlinear dynamic model of a two-span rotor system is constructed based on the hamilton principle and the finite element method. The Musznyska model and the short bearing model are employed to describe the nonlinear seal force and oil-film force. The fourth-order Runge-Kutta method is used to calculate the numerical solutions. The bifurcation diagrams, time-history diagrams, phase trajectories, and Poincare maps are presented to analyze the dynamic behavior of the bearing center and the disk center in the horizontal direction. The numerical results indicate that the rotational speed, the nonlinear seal force, the oil-film force, and the stiffness of the coupling have a significant effect on the stability of the rotor system. The dynamic behavior of the two-span rotor system is more complicated when impacted by the nonlinear seal force and oil-film force.

基于Hamilton原理的双跨转子系统建模和转子动态特性分析

研究双盘双跨转子/轴承/汽封系统在非线性油膜力和非线性汽封力共同作用下的动力学特性，分析了转子转速、密封力、油膜力和联轴器刚度等因素对转子稳定性的影响。 采用Hamilton原理和有限元方法建立双盘双跨转子/轴承/汽封系统模型，使得双跨多节点的转子系统数值求解更加容易。研究分析转子转速、非线性密封力、非线性油膜力和联轴器刚度等因素对转子稳定性的影响，为大型转子系统的设计提供理论基础。 采用Hamilton原理和有限元方法建立双盘双跨转子/轴承/汽封系统模型（图1和2）。应用四阶Runge-Kutta法进行数值求解，并采用轴承处、圆盘处的分岔图、时程图、庞加莱映射图、频率图和相轨迹图等来分析转子系统的动态特性。 1. 通过数值计算分析，转子的转速、非线性汽封力、非线性油膜力和联轴器的刚度对双跨转子的稳定性有重要的影响作用。2. 随着转速的上升，双跨转子系统从最初的稳定运动，到三倍周期运动，到准周期运动和多倍周期运动交替出现，运动特性相比单跨转子系统要更为复杂。
Hamilton原理；双盘双跨转子系统；非线性汽封力；动态特性

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