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. (C) 2001 Academic Press. [References: 14]
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