ASTM D1388-2008 Standard Test Method for Stiffness of Fabrics《织物硬度的标准试验方法》.pdf

1、Designation: D 1388 08Standard Test Method forStiffness of Fabrics1This standard is issued under the fixed designation D 1388; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indic

2、ates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of stiffnessproperties of fabrics. Bending length is measured and flexuralrigidity is calculated. Two procedures are provi

3、ded.1.1.1 Option ACantilever Test, employing the principle ofcantilever bending of the fabric under its own mass.1.1.2 Option BHeart Loop Test, employing the principleof a loop formed in a fabric strip and hung vertically.1.2 This test method applies to most fabrics includingwoven fabrics, air bag f

4、abrics, blankets, napped fabrics, knittedfabrics, layered fabrics, pile fabrics. The fabrics may beuntreated, heavily sized, coated, resin-treated, or otherwisetreated.1.3 The values stated in SI units are to be regarded as thestandard. The U.S. customary units may be approximate.1.4 This standard d

5、oes 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 applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM St

6、andards:2D 123 Terminology Relating to TextilesD 1776 Practice for Conditioning and Testing TextilesD 2904 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally Distributed DataD 2906 Practice for Statements on Precision and Bias forTextiles3D 3776 Test Methods for Mass

7、 Per Unit Area (Weight) ofFabricD 4850 Terminology Relating to Fabrics and Fabric TestMethods3. Terminology3.1 For all terminology relating to D13.59, Fabric TestMethods, General, refer to Terminology D 4850.3.1.1 The following terms are relevant to this standard:bending length, cross-machine direct

8、ion, CD, fabric, flexuralrigidity, machine direction, MD, stiffness.3.2 For all other terminology related to textiles, refer toTerminology D 123.4. Summary of Test Method Options4.1 Option A, Cantilever TestA specimen is slid at aspecified rate in a direction parallel to its long dimension, untilits

9、 leading edge projects from the edge of a horizontal surface.The length of the overhang is measured when the tip of thespecimen is depressed under its own mass to the point wherethe line joining the top to the edge of the platform makes a0.724 rad (41.5) angle with the horizontal. From this mea-sure

10、d length, the bending length and flexural rigidity arecalculated.4.2 Option B, Heart Loop TestA strip of fabric is formedinto a heart-shaped loop. The length of the loop is measuredwhen it is hanging vertically under its own mass. From thismeasured length, the bending length and flexural rigidity ar

11、ecalculated.5. Significance and Use5.1 Both test options in this test method are consideredsatisfactory for acceptance testing of commercial shipmentssince current estimates of between-laboratory precision areacceptable and the method is used extensively in the trade foracceptance testing.5.1.1 In c

12、ase of a dispute arising from differences inreported test results when using this test method for acceptancetesting of commercial shipments, the purchaser and the sup-plier should conduct comparative tests to determine if there isa statistical bias between their laboratories. Competent statis-tical

13、assistance is recommended for the investigation of bias.As a minimum, the two parties should take a group of testspecimens that are as homogeneous as possible and that arefrom a lot of material of the type in question. Test specimens1This test method is under the jurisdiction ofASTM Committee D13 on

14、 Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1, 2008. Published October 2008. Originallyapproved in 1956. Discontinued 1995 and reinstated as D 1388 96. Last previousedition approved in 2007 as D 138807a.2For reference

15、d 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.3Withdrawn. The last approved version of this historical standard is refere

16、ncedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.should then be randomly assigned in equal numbers to eachlaboratory for testing. The average results from the twolaboratories should be compared using the appropriat

17、e statis-tical analysis and an acceptable probability level chosen by thetwo parties before testing is begun. If a bias is found, either itscause must be found and corrected or the purchaser and thesupplier must agree to interpret future test results with consid-eration to the known bias.5.2 In gene

18、ral, these procedures are more suitable for testingwoven fabrics than knit fabrics.5.3 The Cantilever Test Option is the preferred procedurebecause it is simpler to perform. It is, however, not suitable forvery limp fabrics or those that show a marked tendency to curlor twist at a cut edge.5.4 The H

19、eart Loop Test Option is suitable for fabrics thatshow a tendency to curl or twist.5.5 Both options can provide a correlation with a subjectiveevaluation of a given fabric type. That is, a higher numberrepresents a stiffer fabric.5.6 The stiffness of a fabric may change with storage.5.7 No evidence

20、has been found showing that bendinglength is dependent on the width. The tendency for specimensto curl or twist will affect the result, because of the rigidityprovided at the edge. Consequently, the wider the strip, the lessimportant is the edge effect.6. Apparatus6.1 Option ACantilever Bending Test

21、er4(Fig. 1).6.1.1 Horizontal Platform, with a minimum area of 38 by200 mm (1.5 by 8 in.) and having a smooth low-friction, flatsurface such as polished metal or plastic. A leveling bubbleshall be incorporated in the platform.6.1.1.1 Indicator, inclined at an angle of 0.724 6 0.01 rad(41.5 6 0.5) bel

22、ow the plane of the platform surface.6.1.1.2 Movable Slide, consisting of a metal bar not lessthan 25 by 200 mm (1 by 8 in.) by approximately 3 mm (18 in.)thick and having a mass of 270 6 5 g (0.6 6 0.01 lb).6.1.1.3 Scale and Reference Point, to measure the length ofthe overhang.6.1.1.4 Specimen Fee

23、d Unit, motorized4(see Fig. 1) set to120 mm/min (4.75 in./min) 65 %, or manual equivalent.6.1.2 Cutting Die25 6 1mmby2006 1mm(16 0.04in. by 8 6 0.04 in.).6.2 Option BHeart Loop Tester.6.2.1 Clamp and Stand, for hanging the specimen.6.2.2 Scale, suitably mounted on the stand for measuring thelength o

24、f the specimen loop and calibrated either in cm (in.) ordirectly in bending length.NOTE 1If a constant strip length is adopted, the scale may becalibrated to read directly in units of bending length.6.2.3 Brass Bars, two, 25 3 75 3 3 6 0.1 mm(1 3 3 3 0.1256 0.005 in.).6.2.4 Pressure Sensitive Tape.6

25、.2.5 Jig, constructed to allow positioning of the two barswith their inner edges parallel and at a distance from each otherequal to the selected strip length.7. Sampling and Test Specimens7.1 Lot SampleAs a lot sample for acceptance testing,randomly select the number of rolls or pieces of fabric dir

26、ectedin an applicable material specification or other agreementbetween the purchaser and the supplier. Consider the rolls orpieces of fabric to be the primary sampling units. In theabsence of such an agreement, take the number of fabric rollsspecified in Table 1.NOTE 2An adequate specification or ot

27、her agreement between thepurchaser and supplier requires taking into account the variability betweenrolls or pieces of fabric and between specimens from a swatch from a rollor piece of fabric to provide a sampling plan with a meaningful producersrisk, consumers risk, acceptable quality level, and li

28、miting quality level.7.2 Laboratory SampleFor acceptance testing, take aswatch extending the width of the fabric and approximately 1m (1 yd) along the machine direction from each roll or piece inthe lot sample. For rolls of fabric, take a sample that willexclude fabric from the outer wrap of the rol

29、l or the inner wraparound the core of the roll of fabric, or any end piece.7.3 Direction of TestConsider the long dimension of thespecimen as the direction of test.7.4 Number of Test SpecimensFrom each laboratory sam-pling unit, take four specimens from the machine direction andfour specimens from t

30、he cross-machine direction as applicableto a material specification or contract order.7.5 Cutting Test SpecimensCut the specimens to be usedfor the measurement of machine direction with the longerdimension parallel to the machine direction. Cut the specimensto be used for the measurement of the cros

31、s-machine direction4Apparatus is available commercially.FIG. 1 Example of a Motorized Cantilever Test ApparatusTABLE 1 Number of Rolls, or Pieces, of Fabric in the Lot SampleNumber of Rolls or Piecesin Lot, InclusiveNumber of Rolls or Pieces in Lot Sample1to3 all4to24 425 to 50 5over 50 10 % to a ma

32、x of 10 rolls or piecesD1388082with the longer dimension parallel to the cross-machine direc-tion. Label to maintain specimen identity.7.5.1 Take specimens, representing a broad distributionacross the width and length, preferably along the diagonal ofthe laboratory sample, and no nearer the edge tha

33、n one-tenth itswidth. Ensure specimens are free of folds, creases, or wrinkles.Avoid getting oil, water, grease, etc. on the specimens whenhandling.7.5.2 Cantilever TestCut test specimens 25 by 200 mm,61mm(1by8in.6 0.04 in.).7.5.3 Heart Loop TestNo standard size for the test speci-men is required. C

34、ut test specimens 50 mm (2 in.) longer thanthe selected strip length to allow for clamping at the ends. SeeTable 2.7.5.3.1 Select a specimen width at least 25 mm (1 in.) andno more than 75 mm (3 in.) with respect to the tendency of thefabric to curl. For fabrics having a slight tendency to curl, a 2

35、56 1mm(16 0.04 in.) wide specimen has been found to besatisfactory. As the tendency to curl becomes greater, increasethe width up to a maximum of 75 mm (3 in.).7.5.3.2 Make several trial tests using various strip lengthsselected from Table 2. Select a suitable strip length for acorresponding loop le

36、ngth from Table 2, such that the bendinglength is relatively independent of strip length.NOTE 3Strip length is the circumferential length of the unclampedportion of the specimen.NOTE 4Specimen strip widths greater than 75 mm (3 in.) have notbeen investigated and are not recommended since reliability

37、 of results arequestionable.NOTE 5The bending length using the heart loop option is not entirelyindependent of the strip length. In general, the bending length rises withthe strip length up to a value that remains relatively constant as the striplength is further increased. An additional rise may fu

38、rther be encounteredfor much longer strip lengths. Whenever possible, compare fabrics in therange where bending length is independent of strip length.8. Preparation of Test Apparatus and Calibration8.1 Option ACantilever Test:8.1.1 Set the tester on a table or bench with the horizontalplatform and i

39、nclined reference lines. Adjust the platform tohorizontal as indicated by the leveling bubble.8.1.2 Verify that the bend angle indicator is at the 0.724 rad(41.5) angle marked on the scale.9. Conditioning9.1 Precondition the specimens by bringing them to ap-proximate moisture equilibrium in the stan

40、dard atmosphere forpreconditioning textiles as directed in Practice D 1776, unlessotherwise directed in a material specification or contract order.9.2 After preconditioning, bring the test specimens to mois-ture equilibrium for testing in the standard atmosphere fortesting textiles as directed in Pr

41、actice D 1776 or, if applicable,in the specified atmosphere in which the testing is to beperformed, unless otherwise directed in a material specificationor contract order.10. Procedure10.1 Test the conditioned specimens in the standard atmo-sphere for testing textiles, which is 21 6 1C (70 6 2F) and

42、65 6 2 % relative humidity, unless otherwise directed in amaterial specification or contract order.10.2 Option ACantilever Test:10.2.1 Remove the movable slide. Place the specimen onthe horizontal platform with the length of the specimen parallelto the platform edge. Align the edge of the specimen w

43、ith theline scribed on the right-hand edge of the horizontal platform.NOTE 6When known, place the specimen face-side up.10.2.2 Place the movable slide on the specimen, beingcareful not to change its initial position.10.2.3 For automatic testers, turn the tester switch on andwatch the leading edge of

44、 the specimen closely. Turn theswitch off the instant the edge of the specimen touches theknife edge.10.2.4 For manual testers, move the clamped specimen byhand in a smooth manner at approximately 120 mm/min (4.75in./min)6 5 % until the edge of the specimen touches the knifeedge.10.2.5 Read and reco

45、rd the overhang length from the linearscale to the nearest 0.1 cm (0.1 in.).NOTE 7If the specimen has a tendency to twist, take the referencepoint at the center of the leading edge. Do not measure specimens thattwist more than 0.785 rad (45).10.2.6 Test the face and back of both ends of each specime

46、nfor a total of four readings per specimen.10.3 Option BHeart Loop Test:10.3.1 Place the two bars parallel to one another on ahorizontal surface such that the inner edges are separated by adistance equal to the selected strip length (see 6.2.5).10.3.2 Lay the test specimen across the two bars with t

47、heouter edge approximately 5 6 1 mm (0.5 6 0.005 in.) from oneend of each bar.10.3.3 Attach one end of the specimen strip to one bar usingpressure-sensitive tape, being careful to align to one edge ofTABLE 2 Table of Bending LengthsLoop Length,cmBending Length, cm15-cm StripLength20-cm StripLength25

48、-cm StripLength4.0 2.19 . .4.2 2.07 . .4.4 1.99 . .4.6 1.86 3.44 5.434.8 1.76 3.30 5.165.0 1.65 3.17 4.915.2 1.56 3.03 4.715.4 1.45 2.90 4.535.6 1.35 2.80 4.365.8 1.25 2.67 4.206.0 1.14 2.57 4.066.2 1.04 2.47 3.926.4 0.93 2.37 3.806.6 0.81 2.26 3.676.8 0.69 2.16 3.567.0 0.53 2.06 3.457.2 . 1.96 3.34

49、7.4 . 1.86 3.217.6 . 1.76 3.127.8 . 1.66 3.028.0 . . 2.918.2 . . 2.828.4 . . 2.72D1388083the bar. Apply just enough tension to the specimen to hold ittaut, but without stretching, and attach the other specimen endto the second bar in a similar manner.10.3.3.1 A suitable procedure for mounting and measuringthe specimen is the use of two brass bars to which the specimenstrip is fastened. The bars and the attached specimen strip areclamped to the stand in a suitable vertical position in front ofa scale calibrated either in cm (in.) or directly in bendi