Bifurcation of a elastic nonlinear rotor-bearing system

In order to solve the severe vibration of rotor within some parameter domains under the action due to the nonlinear oil film force and with necessary consideration accorded the characteristics of a nonlinear rotor bearing system, the chaos of a elastic rotor system using short bearing model, the variation of some parameters is analysed using the dynamics and nonlinear dynamics theory with the Poincare maps and numerical integral method. The results of calculation shows that may undergo doubling bifurcation and quasio periodic motions. In some typical parameter regions the bifurcation diagrams, the time histories, the phase portrait, the Poincare maps and the frequency spectrums of the system are acquired with numerical integral method. They demonstrate some motional state of the system. The results of analysis provide the theoretical reference for designing and safe operation of this system.