轴承-转子系统的分岔与混沌特性研究

Bifurcations and Chaos of Journal Bearing-Rotor System

利用一种精确的非稳态非线性油膜力模型求得油膜力。以无量纲偏心和一个反映多种影响因素的综合参数为分岔变量 ,用数值积分法在广泛的参数变化范围内研究了轴承 -转子系统运动的变化规律 ,作出了分岔图。借助Poincare映射和 L yapunov指数分析了系统的运动形态。结果表明 ,利用该油膜力模型可从不同角度发现由倍周期分岔导致的混沌现象和概周期运动等复杂的非线性动力学行为。随着参数的变化 ,复杂的运动区域中间会出现简单的运动区域。这为合理设计系统参数以避开危险区域提供了依据。

The nonlinear oil film force of a short journal bearing is obtained by an accurate unsteady model. The characteristics of motion of a journal bearing Jeffcott rotor system are inverstigated by numeric intergal. Several bifurcation diagrams are given where the parameters used are dimensionaless eccentricity and a comprehensive parameter,which mirrors many factors such as rotor weight,viscosity of lubricating oil and freeplay in the bearing.The patterns of the motion of the system are analyzed by the help of Poincare mapping and several Lyapunov indexes . The conclusions derived from this work are:1.When the nonlinear oil film force is considered, the chaos induced by double period bifurcation and quasi period motion may be discovered from different changing parameters;2.There are some simple motion in the complicated regions of motion when parameters are changing.The result alffords a sound basis for an appropriate choice of parameters to avoid dangerous regions of motion.