INTRODUCTION: In Alpine skiing, a skier steers his skis by actions like edging, leaning inwards, angulations, leaning forwards or backwards. We study the influence of such actions by augmenting ski-snow interaction to our skier model. The models for the skier [1] and the ski-snow interaction [2] are validated. With the skier model [1] consecutive turns could be simulated when the track of one ski is given by a spline curve. The purpose of the present work is to study the influence of the above actions for varying snow conditions characterized by the ski-snow interaction model. METHOD: The skier model consists of seven segments: trunk, left and right thighs, shanks, and skis. The skis are modeled as Euler-Bernoulli beams with correct geometric and mechanical properties such as length, width, side cut, thickness, camber, bending and torsional stiffness. We implemented spherical joints at the hips and rotational joints at knees and ankles. The joint angles are kinematically driven. The ski-snow contact is locally determined on the tangential plane to the snow surface. Applied forces are weight and ski-snow contact forces. The ski-snow penetration force is the product of the snow hardness and the cross section of the displaced snow volume. The ski-snow shear is restricted by the product of the ultimate shear stress of snow and the penetration depth. The Newton-Euler equations of motion are formulated in descriptor form and solved by a DAE code. Starting from a reference run, we vary the skier's actions mentioned in the introduction and study their influence on the turn radii. RESULTS/DISCUSSION: The combined model (rigid skier segments, Euler-Bernoulli beams, ski-snow interaction) was tested in a preliminary setting. Rots of simulated ski tracks will be presented at the Conference. With Howe's skiing equation for carved tums [3], one can compute turn radii using the slope inclination, the skier's velocity and traverse angle, and the side cut of the skis. We want to compare the turn radii predicted by the skiing equation with our results where also skidding occurs. CONCLUSION: With our model, one can simulate consecutive turns in Alpine skiing. Parameter studies are given as first applications. We look forward to use the model for steering the skis. For performance and injury investigations further improvements are necessary, for example adding a musculoskeletal model.
© Copyright 2010 Book of Abstracts. 5th International Congress on Science and Skiing, Dec. 14 - 19, 2010, St. Christoph am Arlberg. Veröffentlicht von University of Salzburg, Interfakultärer Fachbereich Sport- und Bewegungswissenschaft/USI. Alle Rechte vorbehalten.