Research On Nonlinear Dynamic Behaviors Of Rotor System With Rubbing Fault

The rotor system is not only an important component part of rotating machinery, but also crucial part of some machine such as rotor pump. Impact rubbing of rotor system is one of the common faults, as one of the most prime nonlinear fault, its vibration is characteristic of strong nonlinearity, which influence the normal operation of these machine. Therefore, analyzing the dynamic characters of the system has great significance to both optimization design of structure and safe stable run of system.On the basis of nonlinear vibration theory and dynamic theory of rotor, the dynamic model of local rubbing Jeffcott rotor system with two rigidity supports was established. Nonlinear dynamic behaviors of rotor system caused by local rubbing fault were studied based on the combination of thought of Shouting method and Runge-Kutta method. The bifurcation diagram and some typical phase map, Poincarémapping sections, rotor shaft locus, time history and amplitude spectra of rotor system response and so on were obtained from numerical simulation. According to what had been obtained, complex nonlinear dynamic behaviors of these nonlinear vibration systems, including periods, quasi-periods, bifurcation of double periods, converse bifurcation of double periods, and chaos motions and so forth, were analyzed. The transformation process of rotor system with rubbing fault from periods motions to chaos motions was detailedly described. The effects of frequency ratio, friction coefficient, eccentricity mass, stiffness ratio and damping ratio on both periods and chaos motions were discussed. Finally, nonlinear characteristics of rotor system with rubbing fault were validated. The conclusions are of great significance to identify and diagnose the rubbing fault of rotor system.