On irreversible thermodynamics for wear prediction

In June of 2000, the authors of this paper reported an experimental study in which degradation in the form of wear of model machinery component-pairs was made on an accelerated testing basis. Concomitant measurement of entropy flow was made by means of a simple calorimeter. Results showed a strong correlation between the referenced wear and the production of entropy flow. We designate this previous work as Category I, in which the normal load is sufficiently high that the heat generated by wear, in a boundary lubrication regime, is much larger than the heat generated by shearing of the lubricant. The present paper treats what we shall call Category II, in which the heat generated by shearing of the lubricant is larger than the heat generated by wear. This includes the limiting case wherein there is neither wear nor production of entropy flow. Again we invoke the laws of thermodynamics, which led us to the conclusion that normalized wear is strongly correlated to normalized entropy flow.