Temperature Rise in Sliding Solids: Influence of Contact Pressure and Temperature on Thermal Conduction

Abstract

Accurate estimation of temperature rise for sliding solids is still challenging. Part of the challenge is accounting for the actual thermal behavior of the solids while sliding (i.e., the nonlinear effects taking place because of sliding conditions and their evolutionary path). Conventionally, only temperature-induced influence on transport properties has been considered. However, thermal properties of the solids also depend on contact stress, the rate of strain, and the rate of heat generation. The contact stress within the mechanically affected zone, even considering the hardness of the softest of the sliding pair, can reach several thousand times the value of atmospheric pressure. Under such a condition, thermal conductivity of many materials show a different behavior than that manifested under standard conditions. This work considers such an influence and its effect on the evolution of temperature. The results show that conventional estimates can considerably under-estimate the actual temperature rise. It is also shown that initial loading, may result in the contacting materials behaving as a layered structure, with each layer having a different capacity of thermal load dissipation. Depending on the distribution of that capacity, dissipation of friction heat may be constrained which may accelerate wear.