Probability of Scuffing in Lubricated Contacts

An analytical determination of the probability of scuffing is presented and used to modify and extend a computer program that was the subject of earlier work. The program identifies conditions that produce boundary or mixed lubrication with asperity overlaps for which the plasticity index is greater than 0.6. It then imposes, as a necessary prerequisite for scuffing, the condition that the surface bulk plus flash temperature is high enough to cause significant desorption of adsorbed lubricant film. For such conditions determination of the probabilities of asperity contact and of plastic asperity contact provide upper and lower bounds respectively to the probability of scuffing. It is shown that in this way critical ranges of conditions can be clearly distinguished from ranges for which scuffing is unlikely.