The Vibrational Characteristics of a Cracked Rotor with Pedestal Looseness
Liu Yuanfeng,Zhao Mei,Zhu Houjun
(The State Key Lab. of Vibration, Shock and Noise, Shanghai Jiaotong University Shanghai, 200030)

Abstract: The vibrational characteristics of a cracked rotor with pedestal looseness are investigated in this paper. The differential equations of motion are established for a cracked Jeffcott rotor system with pedestal looseness. The differential equations are solved by Runge-Kutta method to obtain the response of the system. The bifurcation diagrams are obtained by using the rotating speed as the control parameter. Some orbits and Poincare's maps at different rotating speeds are analyzed. The bifurcation diagrams and the different shapes of Poincare's maps indicate that there exist some parameter regions in which the vibration is chaotic. The results show that this system is more complex than a crack ed rotor without pedestal looseness, and this will be helpful for the diagnosis of cracks in a rotor system.
Keywords: cracked rotor system, pedestal looseness, nonlinear dynamics.