Dynamic simulation and experimental study of an asymmetric double-disk rotor-bearing system with rub-impact and oil-film instability

Abstract

This study deals with numerical analysis and experimental investigations where the nonlinear dynamic behaviors of an asymmetric double-disk rotor-bearing system are reproduced considering rub-impact and oil-film instability. A dedicated experimental setup was designed to validate the interaction between rubs and oil-film vibration. A model considering nonlinear rub-impact forces and nonlinear oil-film forces is put forward to analyze the complicated nonlinear vibrations of the rotor-bearing system. The experimental study focuses on the interaction of oil-whirl/whip and rub-impact faults, and the results show that the oil-whirl is restrained or even removed, but the whip is uninfluenced when the rub becomes heavy contact. The numerical simulation focuses on the effect of eccentricity and the stator stiffness on the onset of instability and nonlinear responses of the rotor-bearing system by using bifurcation diagrams, Poincare maps, frequency spectrum and three-dimension spectral plots. Agreeing with the experimental results, the results from simulation indicate that the motion of system becomes simple and the oil-whirl gets diminished or even disappeared, but the whip keeps unchanged when the eccentricity or the stator stiffness increases. The research discloses the worthy energy exchange phenomenon of multi-fault system and presents the nonlinear dynamical characteristics of the interaction between rub-impact and oil-film instability for such a rotor-bearing system.