Effect of Different Bearing Ratios on the Friction between Ultrahigh Molecular Weight Polyethylene Ski Bases and Snow.
The purpose of this study was to analyze the effect of surfaces with different bearing ratios, but similar roughness heights, on the friction between ultrahigh molecular weight polyethylene (UHMWPE) and snow. On a linear tribometer positioned inside a cold chamber, the different samples were tested over a wide range of velocities and snow temperatures. The surface roughness was measured with a focus variation microscope and analyzed using the bearing ratio curve and its parameters. The surface energy was investigated by measuring the contact angles of a polar (water) and nonpolar (diiodmethane) liquid. The friction tests showed that the bearing ratio had a major effect on the friction between UHMWPE and snow. For temperatures close to the melting point a surface with wide grooves and narrow plateaus (nonbearing surface) performed well. For cold conditions, the friction was less for a surface with narrow grooves and wide plateaus (bearing surface). Interpretations of the results are given on the basis of mixed friction, with lubricated friction being dominant at higher snow temperatures and solid-solid interaction at lower ones.
Department of Sport Science, University of Innsbruck , Fuerstenweg 185, 6020 Innsbruck, Austria.
Sebastian
S
Rohm
Department of Sport Science, University of Innsbruck , Fuerstenweg 185, 6020 Innsbruck, Austria.
Christoph
C
Knoflach
Department of Sport Science, University of Innsbruck , Fuerstenweg 185, 6020 Innsbruck, Austria.
Werner
W
Nachbauer
Centre of Technology of Ski and Alpine Sports, Fuerstenweg 185, 6020 Innsbruck, Austria.
Michael
M
Hasler
Centre of Technology of Ski and Alpine Sports, Fuerstenweg 185, 6020 Innsbruck, Austria.
Lukas
L
Kaserer
Centre of Technology of Ski and Alpine Sports, Fuerstenweg 185, 6020 Innsbruck, Austria.
Joost
J
van Putten
Department of Material Technology, University of Innsbruck , Technikerstrasse 13, 6020 Innsbruck, Austria.
Seraphin H
SH
Unterberger
Department of Material Technology, University of Innsbruck , Technikerstrasse 13, 6020 Innsbruck, Austria.
Roman
R
Lackner
UHMWPE; bearing ratio; friction; snow; surface roughness