Stiffness and damping analysis of a single ehl contact between the rolling element and raceways under wider load and speed ranges

The numerical analysis for the equivalent stiffness and damping of a single EHL contact between the rolling element and raceways under wider load and speed ranges is presented. The unsteady EHL model and free vibration model are applied to describe the motion characteristics of the rolling element. The inlet length and dimensionless natural frequency are determined according to the corresponding working load and speed. The DC-FFT method is implemented in order to increase the computational efficiency associated with elastic deformations and the semi-system approach is applied to ensure solution convergence under severe conditions which makes the analysis of stiffness and damping in the larger ranges of load and speed possible. The numerical results demonstrate that the stiffness increases with the increasing load and decreases with speed. However, the changes of the damping are complex, which are different in various load and speed ranges, especially under heavier load and higher speed. It is also indicated that the stiffness and damping increases with the increase in ambient viscosity and the decrease in pressure-viscosity coefficient.