Lubricating Oil Viscosity of Squeeze Film Damper-Analysis of Dynamic Characteristics of Rotor System Wind-Mill Impact

In this paper, the influence of the oil viscosity of the squeeze film damper on the windmill fixed-point rub-impact of the rotor system was analyzed. Based on the D'Alembert's principle, the dynamic equation of rubbing in a double disc-rolling bearing rotor system considering the effects of nonlinear oil film force, rubbing friction force and supporting bearing force was established, and solving dynamic equations by the fourth-order Runge-Kutta method. The effects of oil viscosity of the squeeze film damper on the dynamic characteristics of the rotor system at windmill fixed-point rub-impact were analyzed by combining Bifurcation diagram, time-domain waveform plots, frequency spectrum plots, axial locus trace plots, and Poincaré cross-sectional plots. The result shows that the viscosity of lubricating oil is a sensitive parameter that affects the response characteristics of the rotor system. As the viscosity of the lubricating oil increases, the rotor system moves from periodic motion to pseudo-periodic motion and finally enters a state of chaotic motion. If the lubricating oil viscosity is too large, the oil film will be locked in damping. The squeeze oil film damper is equivalent to a rigid support, the vibration reduction performance is reduced, and the system operation is more turbulent. This analysis results can provide references for aero-engine vibration control and fault diagnosis.