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An unbalanced rotor dynamic model supported on ball bearings is established. In the model, three nonlinear factors of ball bearing are considered, namely, the clearance of bearing, nonlinear Hertzian contact force between balls and races, and the varying compliance vibrations because of periodical change in contact position between balls and races. The numerical integration method is used to obtain the nonlinear dynamic responses; the effects of the rotating speed and the bearing clearance on dynamic responses are analyzed; and the bifurcation plots, the phase plane plots, the frequency spectra, and the Poincaré maps are used to carry out the analyses of bifurcation and chaotic motion. Period doubling, quasiperiod loop breaking, and mechanism of intermittency are observed as the routes to chaos.

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In this paper, a new rotor-ball bearing-stator coupling system dynamics model is established for simulating the practical whole aero-engine vibration. The main characteristics of the new model are as follows: (1) the coupling effect between rotor, ball bearing, and stator is fully considered; (2) the elastic support and the squeeze film damper are considered; (3) the rotor is considered as an Euler free beam of equal-section model, and its vibration is analyzed through truncating limited modes; (4) nonlinear factors of ball bearing such as the clearance of bearing, nonlinear Hertzian contact force, and the varying compliance vibration are modeled; and (5) rubbing fault between rotor and stator is considered. The Zhai method, which is a new explicit fast numerical integration method, is employed to obtain system’s responses, and the whole aero-engine vibration characteristics are studied. Finally, aero-engine tester including casing is established to carry out rubbing fault experiment, the simulation results from rotor-ball bearing-stator coupling model are compared with the experiment results, and the correctness of the new model is verified to some extent.