Surface texturing has been shown to reduce friction and increase the film thickness in various tribological applications (hydrodynamic bearings, mechanical seals, and cylinder-liner contacts). However, only few studies discuss optimal texturing properties, and most of them focus on the optimal dimple shape. This article proposes an in-depth study on the influence of cavitation and of different texturing parameters, especially the dimple depth, the texture extent, and the dimple aspect, on the hydrodynamic performance of textured contacts. The results are derived numerically, for contacts between plane surfaces that are parallel or inclined with respect to each other. The performance gains (film thickness and friction force) obtained by texturing are evaluated with respect to the performance of smooth contacts. Most notable findings are the optimal extent of the textured region (partial texturing and trapezoidal shape) and the optimal dimple aspect (longitudinal). Cavitation is shown to have a significant influence on the performance of near-parallel textured contacts, although it does not appear to contribute to the generated hydrodynamic lift. It is equally shown that the dimple arrangement with respect to the leading edge is a determining factor for the performance of near-parallel textured sliders.

The article presents a one-dimensional isothermal flow model with analytical solution for partially textured surfaces, nominally parallel. The model allows a simple and elegant parametric analysis of slider performance characteristics (load-carrying capacity, friction force, and friction coefficient) in terms of texture dimensions. It is shown that the friction force and load-carrying capacity do not practically depend on the number of cells. Optimum values of design parameters (dimensionless dimple depth and dimensionless textured length), allowing for maximum load-carrying capacity and minimum friction coefficient, are presented in the dimensionless form. The same model is used to give a phenomenologically based solution for the ‘equivalent step bearing’ in terms of load-carrying capacity or friction coefficient. The results show that the concept of equivalent step bearing is questionable, as the equivalent height of the step bearing is not uniquely determined.

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Despite a large amount of work dedicated to the study of the effects of textured surfaces in tribological pairs, there is still a need for accurate and convincing experimental results to prove the benefi c effects predicted theoretically. This paper presents an original experimental set-up with a partially textured fl at pin sliding on a rotating disc in the presence of a thin lubricating fi lm of constant thickness. The texture was composed of a series of parallel grooves cut on the half of the pin front face. The main objective of the reported work was the experimental assessment of hydrodynamic performances (load capacity and friction force) for parallel, partially textured sliders and the comparison with a similar step slider. Preliminary results have clearly put in evidence the collective hydrodynamic effect of partially textured surfaces. The stepped confi guration has shown greater load capacity with respect to textured confi guration. Copyright