Double Nonlinearity–Unbalance Response of Rotor on Ball Bearings With Squeeze Film Dampers

The nonlinear behavior of rolling-element bearings and squeeze-film dampers is well recognized; stiffness coefficients (and for dampers, damping coefficients also) increase as vibration amplitude increases. In the design of rotating systems using these elements, nonlinear aspects must be accounted for, and support properties chosen to handle the specific imbalance expected. Rolling-element bearings (e.g., ball bearings) are often used in combination with squeeze-film dampers (SFD). However, there seems to be no public information on the interaction of these two nonlinear elements. The purpose of this paper is to analytically document this interaction, and provide design guidance to optimize system performance for normal and extraordinary imbalance levels. Results show that a well-designed SFD in conjunction with a ball bearing performs similar to an optimized linear support with linear bearing, but care must be taken to ensure that the SFD can handle the maximum load encountered.