Effect of Mechanical Preloads on the Dynamic Performance of Gas Foil Bearings Conference Paper uri icon


  • Gas foil bearings (GFBs) enable efficient, reliable and maintenance free operation of high-power-density microturbomachinery (> 200 kW). High speed rotors supported on bump-type GFBs, however, are prone to show large-amplitude subsynchronous motions albeit reaching limit cycle performance. Presently, commercial GFBs are simply modified to introduce a mechanical preload that induces a hydrodynamic wedge to generate more load support and direct stiffnesses. Three metal shims inserted under the bump strip layers and in contact with the bearing housing create a multiple lobe clearance profile at a very low cost. Shaft speed coastdown measurements reveal the rotordynamic performance of a rotor supported on original GBFs and (modified) shimmed GFBs. The later GFBs determine a raise in the rotor-bearing system natural frequency, as expected, and also act to delay the onset speed of large-amplitude subsynchronous motions. Predictions of imbalance response implementing linearized bearing force coefficients are in good agreement with measured amplitudes of synchronous response for both GFB configurations, original and modified.

name of conference

  • STLE/ASME 2008 International Joint Tribology Conference

published proceedings

  • STLE/ASME 2008 International Joint Tribology Conference

author list (cited authors)

  • Kim, T. H., & San Andres, L.

citation count

  • 3

complete list of authors

  • Kim, Tae Ho||San AndreĀ“s, Luis

publication date

  • January 2008