While such investigations yield differing effects dependent on the situation, the common observation of a temperature change has been associated with the presence of mechanical energy, which is required to overcome frictional resistance as sliding at the contact interface occurs. The energy, dissipated through conversion into thermal energy, is manifested as a temperature rise. At the microlevel, this increase can be substantial. A localized change in material properties, an enhancement in chemical reactivity, and ultimately, failure of the mechanical system can result. Attempts to quantify temperature changes have led to the development of straightforward equations associated with the type of. | While such investigations yield differing effects dependent on the situation the common observation of a temperature change has been associated with the presence of mechanical energy which is required to overcome frictional resistance as sliding at the contact interface occurs. The energy dissipated through conversion into thermal energy is manifested as a temperature rise. At the microlevel this increase can be substantial. A localized change in material properties an enhancement in chemical reactivity and ultimately failure of the mechanical system can result. Attempts to quantify temperature changes have led to the development of straightforward equations associated with the type of contact. Although obscured by such situational uncertainties as the coefficient of friction real area of contact time of heat source exposure and the constancy of material properties the computational methods outlined in this discussion are focused on the flash temperature that is the relative change between the surface temperature and bulk temperature of a component due to frictional energy dissipation at the surface. To a designer such an analysis provides an indication of what temperature level to expect when surfaces are in contact provided that the physical and chemical changes that may occur in a surface layer are accounted for. Acknowledgement The authors wish to express their appreciation to the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology for the sponsorship of this work. Frictional Heating Nomenclature In applying the developments associated with frictional heating concepts have emerged that can dramatically affect the integrity of an analysis. The user needs to understand how such parameters as temperature T coefficient of friction . heat partition factor heat source time t Peclet number Pe and real area of contact Ar are interpreted and how they contribute to the heat transfer model employed. Bulk Contact and Flash .
