Abstract
The present work contains a detailed presentation of a test rig for measuring the static and dynamic characteristics of air bearings. The test rig consists of a 60-krpm spindle entraining a shaft guided by a Lomakin hybrid bearing. The test bearing is floating, overhung at one end of the shaft, and mounted on a squirrel cage. The bearing is statically loaded by a spring, and the dynamic excitation is applied by two shakers. Frequency-dependent dynamic coefficients are identified by sweeping the allowable excitation frequencies and by using a transfer function representation of the complex impedances. Test results are presented and compared with theoretical predictions for a cylindrical aerodynamic bearing of 30-mm diameter, L/D = 1, and 22-μm clearance.
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Acknowledgement
The authors are grateful to Région Poitou-Charentes for partially supporting this work.
Review led by Waldek Dmochowski
Notes
1The additional stingers or rods are very similar to the squirrel cage used by squeeze film dampers.
2The index ab was neglected for clarity, but each impedance has a proper approximation.