Influence of anisotropic surface roughness on lubricated rubber friction: Extended theory and an application to hydraulic seals

Lubricated sliding friction: Role of interfacial fluid slip and surface roughness

“…However, real solids have surface roughness on many length scales and most fluids exhibit complex rheology when confined at narrow separation between solid surfaces. Recently, theories, based on the multiscale description of the contact dynamics, have been developed for the sliding dynamics between solids with random roughness on many length scales in fluids with simple shear-thinning rheology [2][3][4][5].…”

“…In this paper we study the influence of wall fluid slip on the velocity dependence of the friction coefficient, the so called Stribeck curve. We extend the wet contact mechanics theory developed elsewhere [2,3] to include the slip length, and present numerical results for different slip lengths for realistic systems. We consider the case of an elastic cylinder with random surface roughness sliding against a flat rigid (low-energy) counter-surface.…”

Microscopic design and optimization of hydrodynamically lubricated dissipative interfaces

“…Among these studies, Persson presented an approach where rough contacts were resolved together with induced long range elastic deformations and the anisotropic macroscopic Reynolds equation was investigated under these conditions. The stress factors were then incorporated into this setting in the work of Persson and Scaraggi in a macroscopically isotropic setting, where was also addressed, and a related anisotropic generalization was subsequently discussed in the work of Scaraggi et al A more detailed discussion of the anisotropic traction formulation may be found in another work of Scaraggi et al, which recovers similar expressions to those which may be found in the work of Benhaboucha et al These studies, including the aforementioned work, are carried out in a simplified setting where only one surface is microscopically nonsmooth (see Section 4). Consequently, the homogenization‐based traction expressions presented earlier are generalizations of these results to the case where both surfaces could be nonsmooth.…”

“…This micro‐texture may be on either surface (top or bottom) and both surfaces can be moving. However, one can show that the results of an homogenization analysis applied to a simpler scenario where the nonsmooth surface is stationary and the smooth one moves can be reused to address the general scenario based on the foregoing results (for the computation of the fluid flux, see the work of Waseem et al and, for the tractions, see the work of Scaraggi et al). In any case, the homogenized response will not display microscopic temporal fluctuations: p 0 = p 0 ( x , t ).…”

“…which, when employed in (52), delivers (51) as desired. The quantities {a ′ , b ′ , e ′ } are easily evaluated, once the particular form of h = h(s) is specified (Section 6.1).…”