BS ISO 6003:2017 pdf download – Alpine skis — Determination of mass and polar moment of inertia — Laboratory measurement method
2 Normative references
There are no normative references in this document.
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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mass of ski
mass of a finished manufactured ski without any mounted parts
Note 1 to entry: Expressed in kilograms.
polar moment of inertia
mass moment of inertia of the ski about its centre of gravity
Note 1 to entry: The unit used to express the polar moment of inertia is the kilogram metre squared.
4 Apparatus
4.1 Weighing device, accurate to ±0,02 kg.
4.2 Fulcrum, for locating the centre of gravity of the ski.
4.3 Time measurement device (stop watch), accurate to at least 0,1 s.
4.4 Measuring device in accordance with Figure 1, consisting of the following parts.
4.4.1 Clamping device A (see Figure 1), consisting of two clamping fixtures.
The top clamping fixture has a hole with a mark to locate the centre of gravity and a further two holes at a distance e from the centre mark for fixation of the filaments B. The recommended dimension for, e, is 25 mm and the mass of the clamping device shall be less than 0,1 kg.
4.4.2 Top plate C, with two holes separated by the distance 2d f ; for the fixation of filaments B. The plate C shall be fixed on a stiff, horizontal beam.
4.4.3 Two filaments B, with equal length, l, which connect the top plate with the clamping device. The ratio d f :l shall be approximately 1:40. With the recommended dimension d f = 25 mm, the length, l, shall be 1 000 mm. The filaments shall be made of materials with low elongation and high strength (for example, tennis string, silk fishing line). The diameter of the filaments shall be not more than 1,0 mm.
5 Sampling and conditioning
5.1 In order to ensure comparability, it is recommended to use one of the following ski sizes if data of measurements are published: — 150 cm, 165 cm or 180 cm. From these three sizes, the one which is most representative for the tested model shall be selected.
5.2 All measurements according to this document shall be taken from a finished manufactured ski without any mounted parts.
5.3 All measurements according to this document shall be taken with a measuring device, which has been conditioned at a temperature of (20 ± 2) °C and a relative humidity of (65 ± 1) % (i.e. the device shall be placed in this atmosphere for at least 24 h before measurement).
6 Calibration of measuring device
Differences in construction between the different measuring devices can lead to different measurement results, which deviate from the theoretical accurate value of the polar moment of inertia. In order to compensate such deviations, it is recommended to determine a correction factor, c, for each measuring device, to correct the measured data and improve reproducibility. The correction factor is determined from the ratio of the calculated polar moment of inertia to the measured polar moment of inertia of a bar of steel with dimensions 0,1 cm × 2 cm × 170 cm. The theoretical polar moment of inertia, I th , is calculated by Formula (1):
a is the length of the bar in metres;
b is the width of the bar in metres;
m is the mass of the bar in kilograms.
7 Procedure Measure the mass of the ski with the weighing device (see 3.1). Place the ski on the fulcrum (see 3.2), to determine the centre of gravity, until it balances. The centre shall be marked with a cross sign. Mount the ski in the clamping device A (see 4.4.1) in such a way that the centre of gravity mark is in the centre of the hole of the top clamping fixture midway between the two filaments. The longitudinal centre axis of the ski shall be perpendicular to a line drawn between the two filaments B (see Figure 1). Let the ski come to rest suspended in the device. Eliminate any swinging motion. It is important that the test area be free of air movement, as this affects test accuracy. With the hand, rotate the ski horizontally about its perpendicular axis through the centre of gravity. Lateral displacement of the centre of gravity exceeding 10 mm shall be avoided. The twist angle should be approximately 25°.BS ISO 6003 pdf download.