Hysteretic damping model for the dynamic response in four-point contact slewing bearings

• Minimum achievable damping in four-point contact slewing bearings was assessed. • Material hysteresis due to hertzian deformation was formulated. • Loss factor was used to account for damping in ball-raceway preloaded contacts. • Potential contact loss was considered in damping formulation. • The damping model was validated via FE simulations. Four-point contact slewing bearings are crucial in orientation applications, where damping significantly influences system vibrations. To correlate experimentally their minimum damping capacity through sine tests, this study develops and evaluates three hysteretic damping models representing material hysteresis due to hertzian ball-raceway deformation. Unlike existing models, these account for preloaded contacts while considering also the potential contact loss between balls and raceways. To achieve this, the material loss factor is used as a representative parameter of the material dissipation capacity, adapted to consider contact loss in preloaded bearings under vibration. The damping models are integrated into a mechanistic model that simulates the axial dynamic response of the bearing and validated through finite element simulations, achieving satisfactory correlation. Consequently, this study provides parametric expressions for minimum damping capacity of these bearings as a function of ball diameter, contact conformity, and material loss factor, with the latter to be correlated experimentally through sine tests.