Inverse Determination of Interfacial Wear Temperatures with a Receding Boundary and the Implications for Tribotesting

Frictionally generated interfacial temperatures are of great interest during tribotesting and candidate materials evaluations, as well as from actual components in service. Unfortunately, it is very difficult, if not impossible, to directly interrogate the interacting surfaces for these temperatures, especially when the wear surface is receding. Though remote measurements of temperature or strain are usually obtainable, they can only hint at the frictional temperatures unless they are just below the surface and, thus, quickly vulnerable to wear damage. In order to overcome these inherent difficulties, a least-squares enforcement of remote temperature data was used with a direct analytical solution for a cylindrical specimen with a receding surface to determine the interfacial temperatures as a function of time. Comparisons between the direct and inverse analytical solutions, as well as resulting interfacial predictions, based on existing data showed excellent agreement and verified the ability of the method to determine temperatures based on remote data. As expected, stray transfer from the lateral surface of the pin, specimen dimensions, as well as the recession velocity of the surface clearly influenced the interfacial temperature history and will therefore have important ramifications for tribotesting and the evaluation of the results.