Bifurcation Characteristics of Unbalanced Rotor - Bearing System

Dynamic model of nonlinear rotor—bearing system is set up using the modified Capone bearing forces models. And the nonlinear dynamics behavior of unbalanced rotor—bearing systems was studied. The system state trajectories, Poincare maps, are also constructed to analyze the typical dynamic behavior of the system．Through the nonlinear dynamic numerical simulation of the system，the dynamic phenomena of the rotor—bearing system caused by oil film forces are clearly distinct. The computational results show that the rotor speed is one of the most important factors of the system dynamic behavior. It presents a periodic, period-doubling motion, quasi-periodic motion, and abundant nonlinear dynamical behavior with the changes of the speed.