Stability and bifurcation of symmetrical rotor in self-acting gas journal bearings

Based on the nonlinear dynamics theory,the stability and bifurcation of a symmetrical rotor supported in self-acting gas bearings were studied.A dynamic model of self-acting gas journal bearings and Jeffcott rotor system was established,meanwhile the finite element method was used to approach the time-dependent Reynolds equation,thus obtaining the gas film force.Furthermore,the longterm nonlinear dynamic behaviors of the system were simulated numerically,so the system state trajectory of journal center was acquired.Moreover,the system state trajectory,phase diagram,bifurcation diagram and power spectrum were adopted to analyze the nonlinear behaviors of system and the stability of unbalanced response.The results show that this method could give a deep understanding of whirling instability of the gas film bearings-rotor system.