STABILITY AND NON-LINEAR RESPONSES OF A ROTOR-BEARING SYSTEM WITH PEDESTAL LOOSENESS

Vibration characteristics of a rotor-bearing system with pedestal looseness are investigated. A non-linear mathematical model containing stiffness and damping forces with tri-linear forms is considered. The shooting method is used to obtain the periodic solutions of the system. Stability of these periodic solutions is analyzed by using the Floquet theory. Period-doubling bifurcation and Naimark–Sacker bifurcation are found. Finally, the governing equations are integrated using the fourth order Runge–Kutta method. Different forms of periodic, quasi-periodic and chaotic vibrations are observed by taking the rotating speed and imbalance as the control parameter. Three kinds of routes to or out of chaos, that is, period-to-chaos, quasi-periodic route and intermittence, are found.