转子—轴承—基础非线性动力学研究

在无限短转子－轴承的基础上，考虑基础在垂直方向的变形，通过分析油膜力，建立了转子－轴承－基础非线性动力学模型。当基础的刚度下降至一定值时，系统中存在内共振情形，结合现代非线性动力学理论和数值方法，研究了系统在临界点附近的复杂动力学行为。指出：当转速为２６７５ｒ／ｍｉｎ时，基础中会存在低幅值的调幅运动；当转速为３０００ｒ／ｍｉｎ时，基础中会存在高幅值的调幅运动，它远远超过了机组的允许振动幅值。本文的结果表明：基础的刚度与转子刚度之间产生内共振是机组出现异常振动的原因之一，在设计中应该避免这种情况

Nonlinear Dynamic Analysisof Rotor Bearing Foundation System

On the assumption of short bearings, consideration the vertical deformation of the foundation, the coupled nonlinear dynamic model of the rotor bearing foundation system is formulated in this paper. The internal resonance will appear in the system when the stiffness of the foundation is reduced to a specific value. The complex dynamic behaviour of the system around the critical point is investigated by using modern theory of nonlinear dynamics and numerical method. The numerical results show that amplitude modulation motion with a tiny amplitude will appear in the foundation at the speed of 2675r/min; when the speed increases to 3000r/min, the amplitude modulation motion with large amplitude which is far larger than the designed amplitude will occur in the foundation. The results show that the internal resonance between the stiffness of the foundation and the rotor is one factor of the abnormal vibration in the rotor system. This case should be avoided in the design of the foundation.