ASTM D6614-2007 Standard Test Method for Stretch Properties of Textile Fabrics - CRE Method《织物拉伸特性的标准试验方法 CRE法》.pdf

1、Designation: D 6614 07Standard Test Method forStretch Properties of Textile Fabrics CRE Method1This standard is issued under the fixed designation D 6614; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A

2、 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 the determination of the amountof fabric stretch and fabric growth after a specified extensionand held for a

3、specified time.1.2 While this method can be used for any fabric, knitfabrics having high stretch are better measured by test methodD 2594.1.3 This test method should not be used to measure thebreaking strength and elongation of woven fabrics, which iscovered in Test Methods D 5034 and D 5035.1.4 The

4、 values listed in either SI units or inch-pound unitsare to be regarded separately as the standard. Within the text,the inch-pound units are shown in parentheses. The valuesstated in each system are not exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalue

5、s from the two systems may result in nonconformancewith specification.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the

6、 applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1776 Practice for Conditioning and Testing TextilesD 2594 Test Method for Stretch Properties of Knitted Fab-rics Having Low PowerD 4849 Terminology Relating to Ya

7、rns and FibersD 4850 Terminology Relating to FabricD 5034 Test Method for Breaking Strength and Elongationof Textile Fabrics (Grab Test)D 5035 Test Method for Breaking Force and Elongation ofTextile Fabrics (Strip Method)3. Terminology3.1 For all terminology relating to D13.59, Fabric TestMethods, G

8、eneral, refer to Terminology D 4850.3.2 For all terminology related to D13.58, Yarns and Fiber,see Terminology D 4849.3.2.1 The following terms are relevant to this standard:fabric stretch, fabric growth, stretch yarn.3.3 For all other terminology related to textiles, refer toTerminology D 123.4. Su

9、mmary of Test Method4.1 Fabric Stretch and Fabric Growth A specified load isapplied to a fabric specimen, using a constant rate of extensiontensile tester at a prescribed rate of extension. After holding atthe specified load for a predetermined time, the length ismeasured. The load is removed from t

10、he specimen and allowedto relax for a specified time. A small amount of force, enoughto remove any wrinkles or folds, is applied and the specimenlength measured. The amount of fabric stretch is calculatedfrom the difference in length prior to load and under load.Fabric growth is calculated from the

11、difference in length priorto loading and after relaxation.5. Significance and Use5.1 This method is used to determine the stretch and growthproperties which a garment made of the fabric may be expectedto exhibit during use.5.2 This is a new method and therefore the history of data isvery small, howe

12、ver the excellent agreement of between-laboratory data suggest this method may be considered foracceptance testing of commercial shipments.5.2.1 If there are differences of practical significance be-tween reported test results for two laboratories (or more),comparative test should be performed to de

13、termine if there is astatistical bias between them, using competent statistical assis-tance. As a minimum, samples used for such comparative testsshould be as homogeneous as possible, drawn from the samelot of material as the samples that resulted in disparate resultsduring initial testing, and rand

14、omly assigned in equal numbersto each laboratory. Other fabrics with established test valuesmay also be used for these comparative tests. The test resultsfrom the laboratories involved should be compared using astatistical test for unpaired data, at a probability level chosenprior to the testing ser

15、ies. If bias is found, either its cause must1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.59 on Fabric Test Methods,General.Current edition approved July 1, 2007. Published August 2007. Originallyapproved in 2000. La

16、st previous edition approved in 2000 as D 661400.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright A

17、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.be found and corrected, or future test results must be adjustedin consideration of the known bias.6. Apparatus6.1 Tensile Testing Machine3, of the CRE type with capa-bility to maintain a constant l

18、oad and measurement of thelocation of the moveable crosshead.6.2 Grips and Jaw Faces, a minimum of 50 mm (2 in.) facesto hold the full width of the specimen.7. Sampling, Selection, and Number of Specimens7.1 Primary Sampling UnitConsider rolls, bolts or piecesof fabric, or cartons of fabric componen

19、ts of fabricated systemssuch as garments to be the primary sampling unit, as appli-cable.7.2 Laboratory Sampling UnitAs a laboratory samplingunit take from the primary sampling unit at least one full-widthpiece of fabric that is 1M (1 yd) in length along the selvage(machine direction), after removin

20、g the first 1M (1 yd) length.For circular knit fabrics cut a band at least 300 mm (12 in.)wide. When applicable, use the entire fabric component of thefabricated systems.7.3 Test Specimen SelectionFrom each laboratory sam-pling unit, take test specimens with the long direction parallelto the stretch

21、 direction. Consider the long direction as thedirection of test. Specimen preparation need not be carried outin the standard atmosphere for testing. Label to maintainspecimen identity.7.3.1 When the end-use fabric component of fabricatedsystems is provided, take specimens from different areas. Thati

22、s, if the product is a garment worn on the upper body, then takespecimens from the shoulder, shirt tail, shirt back and front,and sleeve.7.3.2 For fabric widths 125 mm (5 in.) or more, take nospecimen closer than 25 mm (1 in.) from the selvage edge.7.3.3 For fabric widths less than 125 mm (5 in.), u

23、se theentire width for specimens.7.3.4 Cut specimens representing a broad distribution di-agonally across the width of the laboratory sampling unit. Takelengthwise specimens from different positions across the widthof the fabric. Take widthwise specimens from different posi-tions along the length of

24、 the fabric.7.3.5 Ensure specimens are free of folds, creases, orwrinkles. Avoid getting oil, water, grease, etc. on the specimenwhen handling.7.3.6 If the fabric has a pattern, ensure that the specimensare a representative sampling of the pattern.7.4 Specimen PreparationAs test specimens from eachl

25、aboratory sampling unit, proceed as follows:7.4.1 For woven fabrics, cut two strips 65 by 350 mm (2.5by 14 in.) with the long dimension parallel to the stretchdirection.7.4.1.1 Ravel the strips to form test specimens to 50 6 0.5mm (2 6 0.02 in.) width by taking approximately the samenumber of yarns

26、from each side of the specimen.7.4.2 For knitted and nonwoven fabrics, cut two test speci-mens, 50 6 0.5 mm (2 6 0.02 in.) wide by 350 mm (14 in.)with the long dimension parallel to the stretch direction.8. Conditioning8.1 Condition each sample as directed in Practice D 1776,prior to cutting the tes

27、t specimens.9. Preparation and Calibration of Test Apparatus9.1 Set-up procedures for machines from different manufac-turers may vary. Prepare and verify calibration of the tensiletester using directions supplied by the manufacturer.9.2 Set the distance between the jaw faces 250 6 0.5 mm(10 6 0.02 i

28、n.).9.3 Select an appropriate extension speed. Fabrics with verylittle stretch should be extended at a slow speed and fabricswith high stretch at a faster speed. The extension speed is notcritical to the test but consideration must be given to theresponse of the test apparatus to ensure the machine

29、stopswithout overriding the stop point and the time required toperform the test.10. Procedure10.1 Make all tests in the standard atmosphere for testingtextiles.10.2 Place one specimen in the upper jaw, making sure thelong direction of the specimen is parallel to the sides of the jawfaces.10.3 Place

30、the other end of the specimen in the bottom jaw,applying just enough force to remove any folds or wrinkles.10.4 Start the machine and hold at 1814 6 1.0 g (4.0 6 0.02lb.) for 5 6 0.1 min. The electronically controlled machineshould record all the measurements necessary for the finalcalculations.10.5

31、 If the machine is not electronically controlled, stop thecrosshead at 1814 6 l.0g(46 0.02 lb.) Maintain the load byadjusting the crosshead until 5 6 0.1 min. has elapsed.Measure the distance between the jaw faces.10.6 Return the crosshead to the starting position and holdfor 5 6 0.1 min.10.7 Move t

32、he crosshead to a position where all the slack isremoved or the load increases above the zero load line.Measure the distance between jaw faces at this point.11. Calculations11.1 Calculate the fabric stretch and the fabric growth ofeach specimen to the nearest 0.2 percent using Eq 1 and 2.Fabric stre

33、tch, percent 5 BA! /A 3 100 (1)Fabric growth, percent 5 CA! /A 3 100 (2)where:A = original distance between jaw faces, (from 9.2)B = distance between jaw faces measured while the speci-mens under 1814 6 1.0g(46 0.02 lb) as directed in10.4 and 10.5, andC = distance between jaw faces measured after re

34、moval ofslack as directed in 10.7.3Apparatus is commercially available.D661407211.2 Calculate the average stretch and fabric growth of allspecimens tested. To the nearest 0.2 % for the laboratorysampling unit and the primary sampling unit.12. Report12.1 State that the specimens were tested as direct

35、ed in TestMethod D 6614. Describe the material or product sampled andthe method of sampling used.12.2 Report the following information:12.2.1 The average percentage fabric stretch and the aver-age fabric growth.13. Precision and Bias13.1 Interlaboratory Test DataAn interlaboratory test wasperformed

36、in April 1997. Following section 8.1, 2 test speci-mens were cut from each laboratory sample and their stretchand growth measured. The averages of percent stretch andgrowth were calculated as in section 11.2. A total of 10specimens from each of three materials were tested in twolaboratories by a sin

37、gle operator in each laboratory. Thisgenerated 5 averages of 2 specimens as directed in section11.2. Using SAS Proc Varcomp4the within-laboratory andbetween-laboratory components of variance as Standard De-viations for percent stretch and percent growth were deter-mined. These results appear in Tabl

38、e 1.13.2 PrecisionFor the components of variance reported inTable 1, two averages of observed values should be consideredsignificantly different at the 95 % probability level if thedifference exceeds the critical differences listed in Table 2.Adetermination is the average of 2 specimens as specified

39、 insection 11.2.13.3 BiasThe procedure of this test method produces atest value that can be defined only in terms of a test method.There is no independent, referee method by which bias may bedetermined. This test method has no known bias.14. Keywords14.1 fabric growth; fabric stretchASTM Internation

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42、addressed to ASTM International Headquarters. Your comments will receive careful consideration at 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,

43、 at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, 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 610-832-95

44、85 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4SAS PROC VARCOMP components-of-variance procedure, available fromSAS Institute, Box 8000, Cary, North Carolina 27511.TABLE 1 Components of Variance, % Stretch, % GrowthSingle-operatorComponentBetw

45、een-operatorComponentPercent Stretch 0.189 0.124Percent Growth 0.104 0.116TABLE 2 Critical Difference, % Stretch, % GrowthNumber ofDeterminations Single-operator Between-operatorPer Average Precision Precision% Stretch 1 0.52 0.632 0.37 0.513 0.23 0.41% Growth 1 0.29 0.432 0.20 0.383 0.13 0.35D6614073