INTRODUCTION: The pressure distribution between ski and snow is an important factor for turns in Alpine skiing describing the interaction between ski and snow (Kaps, 2001; Federolf, 2005). The aim of the present study was to compute the pressure distribution during two consecutive turns using a validated Computer Simulation model. Additionally, the influence of edging and speed of the skier, as well as snow conditions should be quantified. METHOD: A multi-body model of a skier on two skis was developed in order to study carved turns in Alpine skiing. For the skier, a three segment model was used consisting of the trunk and two legs. The position of the skier's center-of-mass was specified with time in order to simulate the up and down, as well as the forward and backward movements during the turn. Each ski was divided into 19 segments. Adjacent segments were connected by two revolute joints allowing bending and torsion. Stiffness and damping properties of the joints were adjusted by means of measurements on real skis. The normal snow reaction force was modeled by a hypoplastic constitutive equation, which takes into account that snow deformations remain. For the lateral snow reaction force, orthogonal metal cutting theory was applied. A reference Simulation was established consisting of two consecutive turns. During these turns, it was assumed that the skier was well balanced in the forward-backward direction. The up and down movement of the skier was not considered. Afterwards edging angles, speed of the skier and snow conditions were varied in the Simulation. RESULTS: The results of the reference Simulation showed that during the turn, pressure shifted continuously from the inner to the outer ski. Most of the pressure was concentrated in the middle of the ski. This became more accentuated as load increased. At higher edging angles pressure shifted from the middle of the ski to the shovel and the tail. By increasing the speed of the skier, the ultimate shear force (limiting value for the lateral force) was reached and skidding became dominant. Snow conditions showed a significant influence on the pressure distribution and the trajectory of the skier at high speed and different edging angles. DISCUSSION: This study quantifies the influence of the edging angle, the speed and the snow conditions on the pressure distribution between the skis and snow, and as a consequence on the trajectory of the skier. Sharp pressure peaks and zones with little Penetration depth should be avoided, because these factors lead to an increased risk of skidding. Here ski manufacturer and the skier are challenged. The strong influence of the edging angle of the skis indicated that the actions of the skier were an important factor in order to perform carved turns. At high speeds and hard snow conditions, edging gained additional importance.
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