Computer aided design of skis

Clerc, Christian; Gaertner, Roger; Trompette, P.

doi:10.1016/0168-874x(89)90002-4

Cited by 8 publications

(8 citation statements)

References 5 publications

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“…A FEM simulation of skis in the situation of a turn is difficult to implement because (a) skis are sandwich structures consisting of several isotropic and non-isotropic material layers the mechanical properties of which are often not well known, and (b) the ski-snow interaction in skiing is a complicated combination of different mechanical processes, in particular, bending and torsion of the ski [1][2][3], penetration of the snow [4][5][6], machining of snow [7][8][9], friction [10][11][12][13][14], and system vibrations [15,16]. Computer simulation programs that have been developed in recent years [6,[17][18][19][20][21][22][23][24][25][26] focus on the calculation of the deformation of the ski in order to predict performance variables, such as the ski radius or the pressure distribution on the running surface of the ski. A limitation of most of these simulation approaches is a severe simplification of the ski-snow interaction processes.…”

Section: Introductionmentioning

confidence: 99%

Finite element simulation of the ski–snow interaction of an alpine ski in a carved turn

Federolf

Roos

Lüthi³

et al. 2010

Sports Eng

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Skiing manufacturers depend on the development of new skis on trial and error cycles and extensive product testing. Simulation tools, such as the finite element method, might be able to reduce the number of required testing cycles. However, computer programs simulating a ski in the situation of a turn so far lack realistic ski-snow interaction models. The aim of this study was to (a) implement a finite element simulation of a ski in a carved turn with an experimentally validated ski-snow interaction model, and (b) comparison of the simulation results with instantaneous turn radii determined for an actual carved turn. A quasi-static approach was chosen in which the skisnow interaction was implemented as a boundary condition on the running surface of the ski. A stepwise linear function was used to characterise the snow pressure resisting the penetration of the ski. In a carved turn the rear section of the ski interacts with the groove that forms in the snow. Two effects were incorporated in the simulation to model this situation: (a) the plasticity of the snow deformation, (b) the influence of the ski's side-cut on the formation and shape of this groove. The simulation results agreed well with experiments characterising snow penetration. Implementation of the groove in the ski-snow interaction model allowed calculation of the instantaneous turn radii measured in actual turns, but also caused significant numerical instability. The simulation contributes to the understanding of the mechanical aspects of the ski-snow interaction in carved turns and can be used to evaluate new ski designs.

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Section: Introductionmentioning

confidence: 99%

Finite element simulation of the ski–snow interaction of an alpine ski in a carved turn

Federolf

Roos

Lüthi³

et al. 2010

Sports Eng

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“…Bending stiffnesses of skis manufactured between 1975 and 1996 have been measured by Sakata & Ito (1997). Finite element methods for calculating the bending of composite skis have been reported by Clerc et al (1989), and Deak et al (1973Deak et al ( , 1975. In the following, analytical methods are described for calculating the effective bending stiffness`EI' and the`¯ex' which are the two parameters generally used to characterize the bending behaviour of skis.…”

Section: Bendingmentioning

confidence: 99%

“…Torsional stiffnesses of skis manufactured between 1975 and 1996 have been measured by Sakata & Ito (1997 2 ). Analytical methods for determining the torsional stiffness have been proposed by Clerc et al (1989) and Deak et al (1973Deak et al ( , 1975. In the following, we present ®nite element methods for determining the effective torsional stiffness GJ along the length of the ski and the forebody and aftbody twists.…”

Section: Torsionmentioning

confidence: 99%

“…Analysis of the damping characteristics of skis is apparently, as yet, unavailable. Free vibration of skis has been studied by Clerc et al (1989) and by Devaux & Trompette (1980) who used ®nite element methods to calculate the natural frequencies and mode shapes.…”

Section: Vibrationmentioning

confidence: 99%

“…Pressure measurements along the bases of skis have been reported by Piziali & Mote (1972) and by Roberts (1986). Finite element models for the pressure distribution on the bases of skis undergoing small deformations have been presented by Clerc et al (1989) and by Pa Èrssinen & Lehtovaara (1991). Here we present a procedure for calculating the pressure distribution along the base of a ski placed on an elastic foundation of depth d f .…”

Section: Pressure Distributionmentioning

confidence: 99%

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Computing the mechanical properties of alpine skis

1999

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Models were developed to calculate the mechanical properties of alpine skis. The skis considered are constructed of layers of materials which may include wood, foam, metal, plastics and fibre‐reinforced composites. The ski may be manufactured with or without camber and sidecut. On the basis of the models, a computer code was written which yields the mass, bending and torsional stiffness distributions along the length, flex, twist, natural frequencies and the pressure distribution along the base of the ski. The computer code was verified by comparing the outputs of the code to laboratory data. The numerical results and the data were in good agreement lending confidence to the models and the supporting computer code.

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