ASTM F779-12(2018)

Standard Test Method for Torsion Characteristic of Alpine Skis

SIGNIFICANCE AND USE
3.1 This test method provides a means for determining the torsional stiffness of Alpine skis. It is not intended to evaluate the data with regard to the quality of the ski.
SCOPE
1.1 This test method covers the measurement of ski forebody torsion and ski afterbody torsion of adult Alpine skis.  
1.2 No limitation to ski size is proposed. This test method is applicable to all Alpine skis.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2018
• ICS: 97.220.20 - Winter sports equipment
• Technical Committee: F27 - Snow and Water Sports
• Drafting Committee: F27.30 - Skiing and Snowboarding Equipment

Relations

• Replaces: ASTM F779-12 - Standard Test Method for Torsion Characteristic of Alpine Skis
• Effective Date: 01-Jul-2018
• Referred By: ASTM F504-05(2022) - Standard Test Method for Measuring the Quasi-Static Release Moments of Alpine Ski Bindings
• Effective Date: 01-Jul-2018

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F779 − 12 (Reapproved 2018)
Standard Test Method for
Torsion Characteristic of Alpine Skis
ThisstandardisissuedunderthefixeddesignationF779;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope M
t
C N·m/deg 5
~ !
F
θ
F
1.1 This test method covers the measurement of ski fore-
2.1.5 moment of torsion, M—the moment in newton-metres
body torsion and ski afterbody torsion of adult Alpine skis.
t
appliedtorotatetheskiaboutitslongitudinalaxiswhentheski
1.2 No limitation to ski size is proposed.This test method is
is clamped according to Fig. 1 and the moment is applied
applicable to all Alpine skis.
according to Fig. 2.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3. Significance and Use
responsibility of the user of this standard to establish appro-
3.1 This test method provides a means for determining the
priate safety, health, and environmental practices and deter-
torsional stiffness of Alpine skis. It is not intended to evaluate
mine the applicability of regulatory limitations prior to use.
the data with regard to the quality of the ski.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Apparatus
ization established in the Decision on Principles for the
4.1 Clamping Fixture, to grip the ski as a vise with a flat,
Development of International Standards, Guides and Recom-
rigid jaw and three clamps with at least 150 +50, −0 mm
mendations issued by the World Trade Organization Technical
spacing between them. One clamp is located at each end of the
Barriers to Trade (TBT) Committee.
fixture and one in the center as illustrated in Fig. 1.The clamps
should be at least 30 mm wide and cover the full width of the
2. Terminology
ski.
2.1 Definitions of Terms Specific to This Standard:
4.2 Torsion Head, shown in Fig. 2, with low-friction mo-
2.1.1 afterbody torsion angle, θ —that angle, in degrees, to
A
ment (≤0.2 N·m) and quasistatic loading system having a
whichtherunningsurfaceisrotatedatPoint Awhenamoment,
clamping fixture described in 4.1. Common devices for this
M, is applied at Point A as shown in Fig. 1.
t
loading system are a weight on a cable wrapped around the
2.1.2 afterbody torsional spring constant, C —the moment
A
head, or a weight on a lever arm rigidly attached to the head.
per degree of rotation of the ski afterbody when the ski is
The torsion head clamping fixture should have a width of 10 6
clamped in accordance with Fig. 1 and the moment applied in
1 mm and a length equal to or greater than the width of the ski.
accordance with Fig. 2.
The base surface of the torsion head fixture to the ski base
M should be in the same plane as the clamping fixture (that is,
t
C N·m/deg 5
~ !
A
θ camber forced out of ski in clamped position).
A
2.1.3 forebody torsion angle, θ —that angle, in degrees, to
4.3 Scale, to measure the torsion angle with an accuracy of
F
whichtherunningsurfaceisrotatedatPoint Fwhenamoment,
0.5°.
M, is applied at Point F as shown in Fig. 1.
t
5. Procedure
2.1.4 forebody torsional spring constant, C —the moment
TS
per degree of rotation of the ski forebody when the ski is 5.1 Test skis at room temperature (23 6 5°C) without
clamped in accordance with Fig. 1 and the moment applied in specificpreconditioning.Torsionheadandclampingfixtureare
accordance with Fig. 2. ad
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