Evaluation Damping Performance for Hydrostatic Bearing Film by Damping Ratio Scaling

Abstract

This paper investigates how to evaluate the damping ratio in practical measurement for hydrostatic bearing which possesses overdamped damping. The traditional methods such as decayed response, band width of resonant peak, transient response of step excitation and hysteresis circle cannot be utilized for get over overdamped behavior. Because the fundamental mode of worktable supported by hydrostatic bearing is overdamped, high modes must be blended into or influenced by this mode. This paper uses the dimensionless frequency responses with damping ratio as parameter of single DOF mass-damper-spring model to generate a scale to evaluate the damping ratio of the fundamental mode from the experimental measurement of impact response. Using this scaling method, this paper has investigated the influences the operation and design parameters of pressure compensations in hydrostatic bearing on the damping performance.