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The Effect of Sliding Speed on Film Thickness and Pressure Supporting Ability of a Point Contact Under Zero Entrainment Velocity ConditionsA unique tribometer is used to study film forming and pressure supporting abilities of point contacts at zero entrainment velocity (ZEV). Film thickness is determined using a capacitance technique, verified through comparisons of experimental results and theoretical elastohydrodynamic lubrication (EHL) predictions for rolling contacts. Experiments are conducted using through hardened AISI 52 100 steel balls, Polyalphaolefin (PAO) 182 and Pentaerythritol Tetraheptanoate (PT) lubricants, and sliding speeds between 2.0 to 12.0 m/s. PAO 182 and PT are found to support pressures up to 1. 1 GPa and 0.67 GPa respectively. Protective lubricant films ranging in thickness between 90 to 2 10 nm for PAO 182 and 220 to 340 nm for PT are formed. Lubricants experience shear stresses between 14 to 22 MPa for PAO 182 and 7 to 16 MPa for PT at shear rates of 10(exp 7)/sec. The lubricant's pressure supporting ability most likely results from the combination of immobile films and its transition to a glassy solid at high pressures.
Document ID
20010016781
Acquisition Source
Glenn Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Thompson, Peter M. (Case Western Reserve Univ. Cleveland, OH United States)
Jones, William R., Jr. (NASA Glenn Research Center Cleveland, OH United States)
Jansen, Mark J. (AYT Corp. Brook Park, OH United States)
Prahl, Joseph M. (Case Western Reserve Univ. Cleveland, OH United States)
Date Acquired
September 7, 2013
Publication Date
December 1, 2000
Subject Category
Nonmetallic Materials
Report/Patent Number
E-12531
NASA/TM-2000-210566
NAS 1.15:210566
Report Number: E-12531
Report Number: NASA/TM-2000-210566
Report Number: NAS 1.15:210566
Funding Number(s)
PROJECT: RTOP 274-00-00
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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