The Numerical Identification of Basins of Attraction for the Vibration Response of the Rigid Rotor with Squeeze Film Dampers

Abstract

The article deals with the computational study of the rigid rotor coupled with squeeze film dampers. Various techniques such as the method of computation of the synchronous response with a circular centred orbit, the harmonic balance method, and the direct time integration method are used to analyse the nonlinear behaviour of the rotor system. The results indicate that the rotor system can exhibit both a synchronous circular response with a large orbit radius and a nonsynchronous response with a quasiperiodic character. However, both responses are undesirable in rotating machinery and should be avoided. The new results are presented to provide insight into the impact of initial conditions on the vibration response via basins of attraction. The simulations show that: (i) the basins of attraction are more sensitive to the choice of the initial velocities than displacements, (ii) the basins of attraction are noticeably dependent on the rotor speed in the region of a nonsynchronous response, and (iii) the border between the basins of attraction can be smooth or without a clear structure. The research brings clear conditions defined by parameters such as the dimensionless SFD constant, unbalance, and rotational speed for the suppression of undesirable nonlinear phenomena. The results suggest that the damper can effectively improve the vibration response of high-speed rotating machinery, but its design must be chosen appropriately.

Research on Sudden Unbalance Response of Rigid-Elastic-Oil Coupled Ball Bearings

“…Moreover, the SFD is highly nonlinear. In addition to the selection of the elastic support stiffness [35] and SFD parameters [36], an important determining factor is the rotor unbalance [37,38], particularly the sudden unbalance caused by blade loss, which has hindered studies on problems related to SFD-bearing-rotor systems.…”

Special Issue on Rotor Dynamics: Theoretical Analysis, Computer and Experimental Modelling, Measurements

“…Schilling and Liebich [5] conducted experimental research on the influence of a nominal bearing clearance on the lift-off behavior and the load-carrying capacity of gas polymer bearings. Molčan et al [6] performed a computational study of a rigid rotor connected to the stationary part by squeeze film dampers. The authors identified several basins of attraction depending on initial conditions.…”