INTRODUCTION: Deformation and movement of a carving ski are determined by its construction and the external forces acting on the ski. Whereas the forces exerted from the skier to the ski have been determined experimentally, the forces building up between ski and snow have so far only been determined numerically [1,2]. The main purpose of the current work was to bridge this gap with a laboratory device which allows to determine the forces on the carving edge in function of snow properties, edging angle, ski load and finally but not last the ski construction and the used bindings and plates. METHOD: The novel measurement device is shown in Figure 1. It consists of a force piston, which presses the ski down against 15 support points. Each support point consists of a shaft, which transmits the applied force over a lever to a load sensor. The position of the shaft is automatically adjusted to satisfy force-snow penetration laws as determined by Federolf [1]. By adjusting the constants in the penetration laws, the edge forces in carving can be measured for different snow conditions. The Position of the force application points can be altered along the ski axis to accommodate Skis of different lengths. Laterally, the points are aligned to follow the ski edge. RESULTS + DISCUSSION: As an example of the obtained results Figure 2 shows the force distribution on the edge of a slalom ski for an applied load of 1500 N and an edging angle of 30° as a function of the snow hardness. The force distribution strongly depends on the snow properties with the distribution being more centered on hard snow. CONCLUSION: A novel device for the determination of forces on the edge of carving skis is operational with its particularity to take into account the snow penetration of the ski. First results show that the force distribution on the edge depends on many Parameters and in particular on the snow hardness. This should be taken into account in the design of new skiing equipment.
© Copyright 2007 4th International Congress on Science and Skiing. Veröffentlicht von University of Salzburg. Alle Rechte vorbehalten.