The effect of fluid viscoelasticity in soft lubrication

Abstract

This study explores the influence of fluid viscoelasticity in soft lubrication, in which elastohydrodynamic lubrication (EHL) plays an important role. Our findings reveal that introducing polymers can significantly reduce the friction coefficient, particularly for high Deborah numbers, i.e., the ratio between the polymer relaxation time and the flow residence time, due mainly to an increased minimum film height. This augmented film thickness reduces the Newtonian pressure contributions, lowering friction. The study highlights the non-linear relationship between Deborah numbers, load, and viscoelasticity effects, as well as the complex interplay between these factors in the Pipkin space analysis. These insights provide a comprehensive understanding of the fluid viscoelasticity in soft lubricated contacts.