The kinetic friction of polyethylen on snow: the influence of the snow temperature and the load

The gliding of polyethylen on snow was examined in laboratory experiments and in field tests under racing conditions. Special emphasis was given to the investigation of the influence of snow temperature and load on the gliding. In laboratory tests, the coefficient of friction (c.o.f.) was measured using a tribometer that was placed in a freezing chamber. The temperature was varied from -25 degreesC to 0 degreesC, and the load was varied from 50 to 300 kPa. The coefficient of friction is strongly dependent on the snow temperature, It is lowest at around -3 degreesC and increases for low snow temperatures (T < -5<degrees>C) as well as for a snow temperature close to 0 degreesC. The influence of the pressure decreases with increasing snow temperature, and above -6 degreesC, there is no difference detectable between different loads. These results are confirmed by gliding tests conducted in the field. At around -3 degreesC, the skis are fastest. The gliding properties are worse for a snow temperature close to 0 degreesC and in the cold temperature range from -20 degreesC to -5 degreesC. Heavier skiers are faster only in this low temperature range; above -6 degreesC, no difference of the gliding properties due to the weight of the skier can be found. (C) 2001 Elsevier Science B.V. All rights reserved.