Roughness Effects on the Dynamic Coefficients of Ultra-Thin Gas Film in Magnetic Recording

[+] Author and Article Information
Wang-Long Li, Cheng-I Weng

Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan 70101

Chi-Chuan Hwang

Department of Mechanical Engineering, Chung Yuan University, Chung Li, Taiwan 32023

J. Tribol 118(4), 774-782 (Oct 01, 1996) (9 pages) doi:10.1115/1.2831608 History: Received June 17, 1994; Revised August 26, 1995; Online January 24, 2008


The stiffness and damping coefficients of a slider gas bearing operating under arbitrary Knudsen number are calculated. A perfect gas is used as the lubricant, and its behavior is described by the modified average Reynolds equation proposed by Makino et al. (1993). The effects of molecular mean free-path on the roughness-induced flow factors are included. The effects of the nondimensional film thickness, Hs0 , the surface characteristics, (γ1 , γ2 ). the inverse Knudsen number, D0 , the nondimensional frequency, Ω, and the modified bearing number, Λb , on the dynamic coefficients are discussed in this paper. As expected, the values of dynamic coefficients for various roughness orientations approach the smooth value as the ratio, Hs0 , becomes greater and greater, and thus the roughness effect is getting smaller and smaller. The air film of two-sided longitudinal oriented roughness is stiffer than the other two-sided oriented cases. The effect on translational damping coefficients for various two-sided oriented roughnesses is reversed as D0 greater than some value, and this value is affected significantly by Λb . Transversely rough stationary case has the lowest critical value of Λb , at which the negative translational damping appears. The results show that the roughness effect and rarefaction effect on dynamic coefficients are significant, and they cannot be ignored for stability analysis.

Copyright © 1996 by The American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.





Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In