Nonlinear Dynamic Analysis of Gas Bearing-Rotor System by the Hybrid Method Which Combines Finite Difference Method and Differential Transform Method

Gas bearings have been widely applied to high-speed rotating machines due their low friction and high rotational speed advantages. Nevertheless, gas lubrication is viscosity compressible. It causes the bearing-rotor system easy produce self-excited vibration, which leads instability of rotor hinders increase speed. necessary study nonlinear behaviors aerostatic vibration system, especially considering distribution mass flexible gyroscopic effects real rotor. In this paper, behavior investigated from viewpoint dynamics. Firstly, dynamics model a bearing established by combining transient Reynolds equation dynamic obtained finite element method (FEM). The solved using hybrid differential transform (DTM) difference (FDM). Then force substituted into FEM equation. end, based on bifurcation diagram, orbit center, frequency spectrum diagram Poincaré map, system’s are studied solution for with Newmark method. Results show that there exists limited cycle motion in autonomous half-speed whirl nonautonomous system.