A Study on the Mechanism of Low-Frequency Vibration Unstability of Nonlinear Rotor System Chen Yushu, Ding Qian, Memg Quan
(Tianjin University, Tianjin, 300072)

Abstract: Two parts are included in this paper:1.local bifurcation of rotor self-excited vibration affected by material internal damping; 2.general approach on dynamics of a rotor/bearing system, in which the turbulent effect on the hydrodynamic lubricating film force is considered. The results show the complicated nonlinear dy namical behaviours in the nonlinear rotor system. The revealing of the low-freq uency vibration is useful in recognizing and protecting the subharmonic resonant failures of rotor.
Keywords: nonlinear rotor, low-frequency vibration, int ernal damping, oil film force, bifurcation.