Investigation of the Slipping Wear based on the Rate of Entropy Generation

Wear is a complicated phenomenon caused by the relative movement of two contacting surfaces compressed together by a normal force. Prediction of the wear, in most cases, requires various experiments and microstructural characterization of the contacting surfaces. Mathematical models based on physical concepts could provide considerable help in understanding the physical behavior and hence the prediction of this phenomenon. Considering the importance of the generated heat in wear, it seems that thermodynamic parameters are suitable measures for wear modeling proposals. One of these thermodynamic parameters is entropy, the rate of generation of which is mathematically modeled for the sliding wear in this work. For this purpose, experimental wear data from two different materials, namely, Steel 4140 and 70-30 Brass were also considered. The results showed a direct relation between the wear depth of 70-30 Brass and the generated entropy. Moreover, a linear relationship was observed between a number of parameter pairs such as 70-30 Brass temperature – rate of entropy generation, wear depth – transferred heat to 70-30 Brass, wear depth – dissipated energy, and rate of entropy generation – dissipated energy. The wear rate also showed a linear relationship with the 70-30 Brass temperature and the rate of entropy generation. The linearity of the “wear depth – rate of entropy generation” suggests the rate of entropy generation as a decent criterion for the prediction and design of the tribo-systems.