A unified shear-thinning treatment of both film thickness and traction in EHD

Scott Bair (1) , Philippe Vergne (2) , Michel Querry (2)

1 Center for High Pressure Rheology
2 LaMCoS - Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne]

A conclusive demonstration has been provided that the nature of the shear-thinning, that affects both film thickness and traction in EHL contacts, follows the ordinary power-law rule that has been described by many empirical models of which Carreau is but one example. This was accomplished by accurate measurements in viscometers of the shear response of a PAO that possesses a very low critical stress for shear-thinning and accurate measurements in-contact of film thickness and traction under conditions which accentuate the shear-thinning effect. The in-contact central film thickness and traction were entirely predictable from the rheological properties obtained from viscometers using simple calculations. These data should be invaluable to researchers endeavoring to accurately simulate Hertz zone behavior since the shear-thinning rheology is extensively characterized and accurate in-contact data are available to test. In addition, a new model has been introduced that may be useful for the rheological characterization of mixtures.

Mots clés: non-Newtonian; shear-thinning; elastohydrodynamic; film thickness; traction

Domaines: Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]

Scott Bair, Philippe Vergne, Michel Querry. A unified shear-thinning treatment of both film thickness and traction in EHD. Tribology Letters, 2005, 18 (2), pp.145-152. ⟨hal-00140809⟩