Ice hardness in winter sports

The goal of this work is to determine the ice hardness for athletic ice surfaces relevant to skating and bobsleigh. The results will be used to adapt F.A.S.T. 1.0, a computational model (Penny et al., 2007) used to calculate the coefficient of friction between a steel blade and ice. An important aspect of the model is the size of the contact area between the blade and the ice surface on which it slides. We assume that the apparent contact area is determined by the ratio of the force applied by the blade onto the ice and the hardness of the ice surface. In order to determine the dynamic ice hardness, we dropped steel balls ranging from 8–540 g onto several different ice surfaces from heights between 0.3 − 1.2 m. The durations of the impacts between the balls and the ice were on the order of 10− 4 s. We determined the ice hardness by measuring the diameter of the indentation craters. Our data suggests that the dynamic ice hardness P in these athletic facilities varies with the temperature of the ice surface T according to, P−(T) = ((−.6 ±.4)T + 14.7 ± 2.1) MPa. Our analysis of the effect of air humidity on ice hardness was inconclusive.

Research Highlights
► New data on ice hardness for athletic ice surfaces.
► Ice hardness varies with surface temperature according to, P−(T) = ((−.6 ± .4)T + 14.8 ± 2.1) MPa.
► Analysis of the effect of air humidity on ice hardness was inconclusive.