ASTM F1722-1996(2003) Standard Test Method for Determining Mass and Moment of Inertia of Alpine Skis《高山滑橇质量与惯性矩测定的标准试验方法》.pdf

1、Designation: F 1722 96 (Reapproved 2003)Standard Test Method forDetermining Mass and Moment of Inertia of Alpine Skis1,2This standard is issued under the fixed designation F 1722; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the

2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers test measurement methods formass and moment of inertia of adult Alpine skis.21.2 No

3、limitation to ski size is proposed. This test method isapplicable to all adult Alpine skis.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, ass

4、ociated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ISO Standards:3ISO 554 Standard Atmospheres for Conditioning and/orTesti

5、ngSpecificationsISO 6003 Alpine SkisDetermination of Mass and PolarMoment of InertiaLaboratory Measurement Method3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 mass of ski, mthe mass of a finished, manufacturedski without any mounted parts, expressed in kilograms.3.1.2 moment

6、 of inertia, Ithe mass moment of inertia ofthe ski about its center of gravity, expressed in kilogram-metressquared.4. Significance and Use4.1 This test method provides a means for determining themass and moment of inertia of adult Alpine skis. It is notintended to evaluate data with regard to the q

7、uality of the ski.5. Apparatus5.1 Weighing Device, accurate to 60.02 kg.5.2 Fulcrum, for locating the center of gravity of the ski.5.3 Time Measurement Device (stopwatch), accurate to atleast 0.1 s.5.4 Measuring Device, in accordance with Fig. 1, consistingof the following parts:5.4.1 Clamping Devic

8、e, A, consisting of two clampingfixtures. The top clamping fixture has a hole with a mark tolocate the center of gravity and two additional holes at adistance, df, from the center mark for fixation of the filaments,B. The recommended dimension for dfis 25 mm, and the massof the clamping device shall

9、 be less than 0.1 kg.5.4.2 Top Plate, C, with two holes separated by the distance2dffor the fixation of filaments, B. The plate, C, shall be fixedon a stiff, horizontal beam.5.4.3 Two Filaments, B, with equal lengths, l, that connectthe top plate with the clamping device. The ratio df:l shall beappr

10、oximately 1:40. With the recommended dimension df=25mm, and the length, l = 1000 mm. The filaments shall be madeof materials with low elongation and high strength (forexample, tennis racket string and fishing line). The diameter ofthe filaments shall be not more than 1.0 mm.6. Sampling and Condition

11、ing6.1 In order to ensure comparability, it is recommended thatone of the following ski sizes be used if the data measured areto be published: 150, 180, or 200 cm. From these three sizes,choose the one that is most representative of the tested model.6.2 All measurements shall be taken from a finishe

12、d, manu-factured ski without any mounted parts.6.3 All measurements shall be taken from a ski that has beenconditioned in a standard atmosphere 20/65 (ISO 554) (that is,the ski shall be placed in this atmosphere for at least 24 h priorto measurements being taken).7. Calibration of Measuring Device7.

13、1 Differences in construction between the different mea-suring devices can lead to different measurement results, whichdeviate from the theoretical value of the polar moment ofinertia. In order to reduce such deviations, it is recommended1This test method is under the jurisdiction of ASTM Committee

14、F27 on SnowSkiing and is the direct responsibility of Subcommittee F27.30 on Skis and Boots.Current edition approved Feb. 10, 2003. Published May 2003. Originallyapproved in 1996. Last previous edition approved in 1996 as F 172296.2This test method is meant to conform in all significant aspects to t

15、he testmethod for determining mass and polar moment of inertia of Alpine skis as set forthin ISO 6003.3Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29

16、59, United States.that a test equipment validation factor, c, be determined foreach measuring device.7.2 The test equipment validation factor is determined fromthe ratio of the calculated moment of inertia to the measuredmoment of inertia of a bar of steel with dimensions 1 to 8 by20 to 30 by 1200 t

17、o 1700 mm. To ensure accurate measure-ments, it is important that the steel bar be level when placed inthe test device. Any vertical displacement of the steel bar mayalter calculation of the test device evaluation factor.7.3 The theoretical moment of inertia, Ith, is calculated fromthe following for

18、mula:Ith5ma21 b2!12(1)where:a = length of the bar, m,b = width of the bar, m, andm = mass of the bar, kg.7.4 Using this theoretical value and the measured value, thetest equipment validation factor, c, can be determined from thefollowing formula:c 5IthI(2)where:Ith= theoretical polar moment of inert

19、ia, andI = measured polar moment of inertia.7.5 The test equipment validation factor, c, should fallwithin a range from 0.9 to 1.1. If c lies outside this range, thetest equipment shall be checked and brought into conformitywith this test method.8. Procedure8.1 Measure the mass of the ski with the w

20、eighing device(5.1).8.2 Place the ski on the fulcrum (5.2) until it balances, todetermine the center of gravity. Mark the center of gravity onthe ski surface.8.3 Mount the ski in the clamping device, A, (5.4.1) in sucha way that the center of gravity mark is in the center of the holein the top clamp

21、ing fixture midway between the two filaments.The longitudinal center axis shall be perpendicular to a linedrawn between the two filaments, B (see Fig. 1).8.4 Let the ski come to rest suspended in the device.Eliminate any swinging motion. It is important that the testarea be free of air movement, as

22、this affects test accuracy.8.5 With the hand, rotate the ski horizontally about its axisof gravity. Lateral displacement of the center of gravityexceeding 10 mm shall be avoided. The twist angle should beapproximately 25.8.6 After displacing the ski, release it to swing freely aroundthe perpendicula

23、r axis through the center of gravity. The timerequired for the ski to complete at least five cycles is recordedwith the stopwatch (5.3). The time for one oscillation, T,isdetermined by the following formula:T 5recorded timen(3)where:n = number of cycles recorded.9. Expression of Results9.1 Mass of t

24、he SkiExpress the mass of the ski, m,inkilograms.9.2 Moment of Inertia of the SkiExpress the moment ofinertia of the ski, I, in kilogram-metres squared, using thefollowing formula:I 5ST2PD2mgdf2l(4)where:T = period of oscillation, s,m = mass of the finished manufactured ski without anyancillary part

25、s, kg,g = acceleration due to gravity, m/s2,df= half-distance between the filaments measured on thetop plate, m, andl = length of the filaments, m.10. Tolerances10.1 Measurement Tolerances:Mass 60.02 kgMoment of inertia 60.02 kg-m2FIG. 1 Measuring DeviceF 1722 96 (2003)210.2 Tolerances on Published

26、DataIf data are publishedby the manufacturer with reference to this test method, thefollowing tolerances shall be observed:Mass 10 %Moment of inertia 10 %11. Report11.1 Report the following information:11.1.1 Reference to this test method,11.1.2 Name of ski manufacturer,11.1.3 Model designation of s

27、ki,11.1.4 Nominal length of ski,11.1.5 Registration number of ski, and11.1.6 Any deviation from this test method, with an expla-nation of the reason for the deviation.12. Precision and Bias12.1 PrecisionThe precision of this test method is cur-rently being determined.12.2 BiasThere should be no bias

28、 in measurement ofmass if the specification in 5.1 is followed. Bias in measure-ment of the moment of inertia is controlled by the testequipment evaluation factor described in Section 7.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any

29、item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical c

30、ommittee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at

31、a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Dr

32、ive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 1722 96 (2003)3