On friction and surface cracking during sliding of ice on ice

As a complement to earlier measurements on the friction of both granular fresh-water ice and S2 columnar salt-water ice, new experiments were performed on the friction of S2 columnar fresh-water ice sliding against itself at low velocities (5 x 10(-7) to 5 x 10(-1) m s(-1)) and at -10degreesC, using the same double-shear device as was used earlier. The results showed that under a given set of experimental conditions the kinetic coefficient of friction of S2 fresh-water ice compares favorably with that of the other two variants. The experiments also revealed friction-induced surface cracks and recrystallized grains. These deformation features are explained, respectively in terms of fracture mechanics and an earlier model of dynamic recrystallization in ice.