Deformation Behavior of Thin Lubricant Films at Elevated Pressure

Abstract

Significant progress has been made over the past year toward understanding the mechanisms which control friction in concentrated contact. The coefficient of friction in concentrated contact is still often dealt with as a disposable parameter in numerical analyses. Boundary and elastohydrodynamic lubrication have been recognized as separate regimes of concentrated contact lubrication since the EHD solution of Ertel-Grubin. However, the delineation of these regimes is nearly always in practice based on the magnitude of the film thickness relative to surface roughness rather than a transition in friction. It has been observed in boundary lubrication and in some aspects of elastohydrodynamic lubrication that friction is nearly Coulombic in nature - the friction coefficient is only weakly dependent upon load and sliding velocity. In some instances the friction coefficient may be so similar in the boundary and EHD regimes that friction alone does not clearly discriminate the transition from one to the other. These attributes of liquid lubrication would seem enigmatic.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1994
Accession Number
ADA281848

Entities

People

  • Scott Bair

Organizations

  • Georgia Tech

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Boundaries
  • Coefficients
  • Constitutive Equations
  • Engineering
  • Equations
  • Friction
  • High Pressure
  • Internal Friction
  • Lubricants
  • Lubrication
  • Materials
  • Mechanical Engineering
  • Numerical Analysis
  • Shear Bands
  • Shear Stresses
  • Stresses
  • Surface Roughness

Readers

  • Combustion and Flow Dynamics.
  • Petroleum Engineering
  • Systems Analysis and Design