Surface texturing and its influence on tribological systems performances represent one of the main research topics nowadays. Textures functionality is initially ensured by correct optimization of its geometrical parameters, but the influence of textures quality is not to be neglected. Therefore, a proper selection of fabrication methods appropriate for each individual application is imperative. The process of selection is somehow exhaustive due to abundance of parameters and selection criterions. Hence, this paper proposes a general classification of texture manufacturing techniques, used nowadays within industrial manufacturing and research platforms, with pertinent description of each process including key advantages and drawbacks concerning their application within mechanical systems.

It has been proven experimentally that surface texturing represents a viable solution for increasing the load-carrying capacity of parallel fluid bearings. Along with several load-supporting mechanisms that have been identified in the literature, the texture geometry remains an important feature. With the main objective of evaluating the effects of the texture geometry, a mass-conserving model is employed. While avoiding the use of the bulk modulus β, the algorithm also deals with the cavitation phenomenon and provides rapid and accurate results. For given operating conditions (supply pressure, surface speed, or lubricant viscosity), essential geometrical features such as size, density, and shape are analyzed in detail. In terms of load support and friction, the results reveal a strong dependence between certain parameters such as the texture cell number and dimple depth, and an increase in the texture density has beneficial effects in most cases. With regard to shape, the influence of this feature proves to be more significant in the case of single-grooved bearings than in the case of textures.

This article is focused on the comparison between experimental and numerical friction forces obtained for a typical hydraulic ‘U’ rod seal. The numerical results are obtained by the inverse hydrodynamic lubrication method. The experimental results have been obtained on an original experimental device capable of measuring the friction force between a rod and two seals. The reciprocating rod speed, the temperature and pressure in the test cell are controlled. Despite the fact that the numerical results correspond to an idealized hydrodynamic problem for smooth surfaces, it was found that the numerical model agrees with experimental data when the predicted film thickness is higher than the rod roughness but largely lower than the seal roughness. This suggests that the roughness of the seal disappears under the pressure in the sealed contact and do not play an essential role in the lubrication mechanisms. However, it is clear that for very small film thickness, the full film lubrication theory for smooth surfaces is not convenient. This may imply that in these conditions mixed lubrication cannot be ignored or that adhesion phenomena, not taken into account by the lubrication theory, can appear in the contact areas.