A method for the dynamic characteristic analysis of a rotor-rolling bearing system influenced by elastohydrodynamic lubrication

The focus of this paper is to investigate the influence of rolling bearing elastohydrodynamic lubrication (EHL) on rotor dynamic characteristics, while proposing an analytical method for addressing this issue. Firstly, the lubricated contact model and dry contact model between the rolling element and inner and outer raceways were separately established based on the theories of EHL and Hertz contact. The load-mutual approach relationship curves were consequently obtained under both conditions. Furthermore, the finite element method is employed to establish a dynamic model of the rotor-rolling bearing system, simultaneously obtaining a one-to-one mapping relationship between load and vibration displacement. Finally, the Newmark-β numerical solution method is improved by incorporating the mapping relationship between load and vibration displacement through interpolation techniques. This allows for obtaining and comparing the vibration characteristics under both dry contact and EHL conditions, while also analyzing the time-varying stiffness of bearings. The results demonstrate that the impact of EHL on the balanced rotor is substantially more pronounced than on the unbalanced rotor. Additionally, under EHL conditions, the bearing exhibits significantly higher equivalent linear stiffness compared to dry contact conditions.