Viscoelastic response of lubricant in an EHL contact under transient bi-directional shear loading

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There is currently great interest in the understanding of physical origins of friction in elastohydrodynamically lubricated (EHL) contacts of machine components, especially those operating under severe conditions. In such contacts, elastohydrodynamic friction is determined almost entirely by a non-Newtonian response of highly pressurized lubricant in the central area of the contact. Moreover, all of the contacts are affected by vibrations and the lubricant film is subjected to transient shear stress. In the current experimental study, an EHL point contact was exposed to steady-state sliding motion in one direction simultaneously with harmonic sliding motion in a perpendicular direction. Friction forces were measured in the both directions of contact by precise load cells. Results of this study indicate the response of viscoelastic behavior of lubricant to transient bi-directional shear loading and they are confronted with the limiting shear stress phenomenon.

There is currently great interest in the understanding of physical origins of friction in elastohydrodynamically lubricated (EHL) contacts of machine components, especially those operating under severe conditions. In such contacts, elastohydrodynamic friction is determined almost entirely by a non-Newtonian response of highly pressurized lubricant in the central area of the contact. Moreover, all of the contacts are affected by vibrations and the lubricant film is subjected to transient shear stress. In the current experimental study, an EHL point contact was exposed to steady-state sliding motion in one direction simultaneously with harmonic sliding motion in a perpendicular direction. Friction forces were measured in the both directions of contact by precise load cells. Results of this study indicate the response of viscoelastic behavior of lubricant to transient bi-directional shear loading and they are confronted with the limiting shear stress phenomenon.

Elastohydrodynamic lubrication; Traction; Shear strength; Viscoelasticity;

21.05.2017

Society of Tribologists and Lubrication Engineers

Atlanta, Georgia, USA

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