Pressure profiles measured within lubricated contacts in presence of dented surfaces. Comparison with numerical models

In this paper, dented contacts have been studied in an EHL ball on disk device under pure sliding conditions. Dents with diameter of half the Hertzian contact radius were positioned in the center of the contact. The measured pressure profiles, obtained from Raman microspectrometry, are very different from those expected. A huge pressure peak is observed at the place where the lubricant leaves the dent, leading to very high pressure gradients. The effect of the dent shoulders is also visible. These results are discussed and compared to numerical ones. Finally, some consequences on life prediction of dented surfaces are presented.