Nonlinear Dynamics Of Rotor-Bearing System

Rotating machinery is one of the most import equipment in national foundation establishment and industry. Rotor-bearing system is the key part of the rotating machinery, and plays a nonreplaceable role in many important fields of industry. A lot of high requirement for stability, load, efficiency, reliability and automation to rotating machinery has been made alone with the development of high speed, heavy load and efficiency. Rotor-bearing system has many nonlinear problems and complex dynamics characteristic. The research on rotor dynamics takes a new look after introducing the theory of modern nonlinear dynamics.Domestic and international scholars did a lot of research effort by the theory of modern nonlinear dynamics, such as bifurcation and chaos behavior on crack rotor system, vibration of oil film, rub-collision rotors, loosening foundation, catastrophe and gradation of rotor trouble. We got many important results, but most of research that focused on single deck rotors with singularity troubles, research coupling troubles of rotor systems is not enough.From simple to complex, there are three multi-decks rotor models supported by two seals bearings in two ends established in this article. First model is a multi-decks rotor with loosening foundation. Second model is rub rotor-bearing system. Force of friction between deck of rotor and stator accords with the coulomb law of friction. Last model is a complex multi-deck rotor system which has coupling troubles of loosening foundation and rubbing.The stability of period response of nonlinear rotor-bearing systems is analyzed by employing the Newmark and shooting methods. The bifurcation rules of period response of elastic rotor system with multi-degree of Freedom are obtained. The motion characteristic of the rotor system is determined according to the fractal dimension of Poincare mapping of phase aspect and frequency spectrums at certain speed and physic parameter of rotor.