POLLUTION SOLIDE DES LUBRIFIANTS, INDENTATION ET FATIGUE DES SURFACES
The objective of the present work is, on one hand, to better understand the phenomenon of surface indentation and, on the other hand, to evaluate the surface fatigue associated with this type of defect . The indentation of the surfaces is the subject of the first part mainly experimental . An original device, associated with a twin disc machine, to impose a controlled level of contamination was constructed and validated. We first studied the probability of passage of a solid particle in EHL contact and describes the mechanisms of indentation. The influence of the nature of the contaminants and operating conditions (load, speed and slide to roll ratio) was the subject of a particular attention to the number, size and shape of the indents observed. In a second part , the consequences of the indentation on Rolling Contact Fatigue life are analyzed from both a theoretical and experimental standpoint . These were ( i ) to identify the damage mechanisms which are causing indents , ( ii ) predict the initiation sites and ( iii ) assessing the importance of the geometry of the indent and operating conditions in the damage process . This work is based on existing codes of calculation. The results of these simulations were compared with experimental results. A good correlation is observed regarding the initiation sites. This work is a first step for predicting the effects of solid contaminants in lubricants on Rolling Contact Fatigue of mechanisms.