Correlations between curling stone frictions and tribology’s Stribeck curve: concepts to consider

The glides of curling stones to the button on curling-sheet ice are composed of three segments: ( i) an initial high-speed travel characterized by mild decelerations (and minor curls); ( ii) a slower-speed segment with visibly greater rates of deceleration (and curl); and ( iii) an abrupt end-of-travel. It is proposed here that these three travel segments correlate with the three well-known frictional regimes of tribology’s Stribeck curve: ( i) a hydrodynamic (wet) frictional regime in which, at high speeds, the generation of frictional heat from shearing stress within a lubricating water film is sufficient to melt ice and fully isolate the rock’s running-band from the ice surface, i.e., from mutually abrasive contact; ( ii) a mixed frictional regime where, with ever-more severe friction and ever-stronger deceleration and thus ever-lower speeds, the generation of frictional heat is progressively less and the lubricating water film becomes ever-thinner, allowing rock and ice asperities to cut ever-more abrasively into their opposing surfaces; and ( iii) a totally dry, highly abrasive frictional regime in which, at very low speeds, lubrication ends because of the lack of sufficient frictional heat to maintain a water film and thus the rock’s advance comes to an abrupt end.