Contact mechanics of rough surfaces: a comparison between theories

In this paper the authors briefly review the most important theories of contact mechanics between randomly rough surfaces. The multiasperity contact theories are here shown under a unifying point of view and compared with the more recent approach developed by Persson. In particular we focus on the relation between the applied load and separation, which is fundamental in many engineering applications as seals, lubrication and wear. We found that the difference between the multiasperity contact models and Persson's theory is not only quantitative, as in case of area-load linearity, but also qualitative. A brief comparison with existing experiments and numerical calculations shows that Persson's predictions should be more accurate.