1、Designation: D5587 14Standard Test Method forTearing Strength of Fabrics by Trapezoid Procedure1This standard is issued under the fixed designation D5587; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of the tearingstrength of textile fabrics by the trapezoid procedure using arecording constant
3、-rate-of-extension-type (CRE) tensile testingmachine.1.1.1 The CRE-type tensile testing machine has become thepreferred test apparatus for determining trapezoid tearingstrength. It is recognized that some constant-rate-of-traverse-type (CRT) tensile testing machines continue to be used.Consequently,
4、 these test instruments may be used when agreedupon between the purchaser and the supplier. The conditionsfor use of the CRT-type tensile tester are included in AppendixX1.1.2 This test method applies to most fabrics includingwoven fabrics, air bag fabrics, blankets, napped fabrics, knittedfabrics,
5、layered fabrics, pile, and nonwoven fabrics. Thefabrics may be untreated, heavily sized, coated, resin-treated,or otherwise treated. Instructions are provided for testingspecimens with or without wetting.1.3 Tearing strength, as measured in this test method,requires that the tear be initiated before
6、 testing. The reportedvalue obtained is not directly related to the force required toinitiate or start a tear.1.4 Two calculations for trapezoid tearing strength areprovided: the single-peak force and the average of five highestpeak forces.1.5 The values stated in SI units are to be regarded as thes
7、tandard. The values stated in inch-pound units may beapproximate.1.6 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 appl
8、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD629 Test Methods for Quantitative Analysis of TextilesD1776 Practice for Conditioning and Testing TextilesD290
9、4 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally Distributed Data (With-drawn 2008)3D2906 Practice for Statements on Precision and Bias forTextiles (Withdrawn 2008)3D4850 Terminology Relating to Fabrics and Fabric TestMethods3. Terminology3.1 For all terminology
10、relating to D13.59, Fabric Testmethods, General, refer to Terminology D4850.3.1.1 The following terms are relevant to this standard:fabric, in textiles; peak force, in tear testing of fabrics; tearingforce, in fabric; tearing strength, in fabrics; yarn distortion (seeFig. 1).3.2 For all other terms
11、related to textiles, refer to Terminol-ogy D123.4. Summary of Test Method4.1 An outline of an isosceles trapezoid is marked on arectangular specimen (see Fig. 2). The specimen is slit at thecenter of the smallest base of the trapezoid to start the tear. Thenonparallel sides of the marked trapezoid a
12、re clamped inparallel clamps of a tensile testing machine. The separation ofthe clamps is increased continuously to apply a force topropagate the tear across the specimen. At the same time, theforce developed is recorded. The force to continue the tear iscalculated from autographic chart recorders o
13、r microprocessordata collection systems.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved Feb. 15, 2014. Published March 2014. Originallyapproved in 1996. Last
14、previous edition approved in 2008 as D5587 08. DOI:10.1520/D5587-14.2For 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 w
15、ebsite.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This test method is considered satisfactory for accep-tance testing
16、of commercial shipments because current esti-mates of between-laboratory precision are acceptable, and thistest method is used extensively in the trade for acceptancetesting.5.2 If there are differences of practical significance betweentest results for two laboratories (or more), comparative testsho
17、uld be performed to determine if there is a statistical biasbetween them, using competent statistical assistance. As aminimum, use the samples for such a comparative test that areas homogeneous as possible, drawn from the same lot ofmaterial as the samples that resulted in disparate results duringin
18、itial testing. Randomly assign the samples in equal numbersto each laboratory. The test results from the laboratoriesinvolved should be compared using a statistical test forunpaired data, at a probability level chosen prior to the testingseries. If bias is found, either its cause must be found andco
19、rrected, or future test results for that material must beadjusted in consideration of the known bias.5.3 The trapezoid tear produces tension along a reasonablydefined course such that the tear propagates across the width ofthe specimen. It is useful for estimating the relative tearresistance of diff
20、erent fabrics or different directions in the samefabric.5.4 Depending on the nature of the specimen, the datarecording devices will show the tearing force in the form of apeak or peaks. The highest peaks appear to reflect the strengthof the yarn components, individually or in combination, neededto s
21、top a tear in fabrics of the same construction. The valleysrecorded between the peaks have no specific significance. Theminimum tearing force, however, is indicated to be above thelowest valleys.5.5 Most textile fabrics can be tested by this test method.Some modification of clamping techniques may b
22、e necessaryfor a given fabric, depending upon its structure. Strong fabricsor fabrics made from glass fibers require special adaptation toprevent them from slipping in the clamps or being damaged asa result of being gripped in the clamps. In some cases, due tofabric constructions, individual yarns m
23、ay not rupture but showa high peak and yarn distortion within the test specimen.Wherever possible, this shall be prevented. If you have tried allof these steps and yarn distortion still occurs, this must beincluded in the report.5.6 The CRE-type is the preferred tensile testing machine.This test met
24、hod allows the use of the CRT-type tensilemachine when agreed upon between the purchaser and thesupplier. There may be no overall correlation, however, be-tween the results obtained with the CRT-type machine and theCRE-type machine. Consequently, these two tensile testerscannot be used interchangeab
25、ly unless the degree of quantita-tive correlation has been established between the purchaser andthe supplier. In any event, the CRE-type machine shall prevail.6. Apparatus6.1 Tensile Testing Machine4, of the CRE-type conformingto the requirements of Specification D76 with autographicrecorder, or aut
26、omatic microprocessor data gathering system.6.2 Clamps, having all clamping surfaces parallel, andcapable of preventing slipping of the fabric specimen during atest, and measuring at least 50 by 75 mm (at least 2 by 3 in.),with the longer dimension perpendicular to the direction ofapplication of the
27、 force.6.2.1 The use of hydraulic or pneumatic clamping systemswith a minimum of 50 by 75-mm (at least 2 by 3-in.) rubber,metal, or padded/coated clamps faces shall be used. The facesshall have an appropriate clamping force at the clamp facesdepending on the type of fabric under test. The pressure s
28、houldbe sufficient to prevent slippage of the fabric specimen fromthe clamps during the test, while ensuring the specimen is notdamaged at the clamps edge. For certain industrial type fabricsa gripping force at the clamps of 13 to 14 kN (2900 to 3111 lbf)is recommended. Manual clamping is permitted
29、providing nofabric specimen slippage in the clamp is observed. When usingmanual clamping, use of torque wrench or other tool isrecommended to consistently achieve 2900-3111 lbf.6.2.2 For some fabrics, to prevent fabric slippage or yarndistortion from the clamp when using clamp faces other thanserrat
30、ed, such as rubber faced clamps, the clamps faces may becovered with a No. 80 to 120 medium grit emery cloth. Securethe emery cloth to the clamps faces with pressure-sensitivetape. Other techniques may also be used such as resins ifnecessary. If fabric slippage or yarn distortion continues tooccur,
31、then serrated or interlocking clamps faces should beused.6.3 Cutting Die or Template, having essentially the shapeand dimensions shown in Fig. 2.7. Sampling and Test Specimens7.1 Lot SampleAs a lot sample for acceptance testing,randomly select the number of rolls or pieces of fabric directedin an ap
32、plicable material specification or other agreementbetween the purchaser and the supplier. Consider the rolls or4Apparatus and accessories are commercially available.FIG. 1 Photograph Showing Yarn Distortion in a Modern Techni-cal Type FabricD5587 142pieces of fabric to be the primary sampling units.
33、 In theabsence of such an agreement, take the number of fabric rollsspecified in Table 1.NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween rolls or pieces of fabric and between specimens from a swatchfrom a ro
34、ll or piece of fabric to provide a sampling plan with a meaningfulproducers risk, consumers risk, acceptable quality level, and limitingquality level.7.2 Laboratory SampleFor acceptance testing, take aswatch extending the width of the fabric and approximately 1m (1 yd) along the machine direction fr
35、om each roll or piece inthe lot sample. For rolls of fabric, take a sample that willexclude fabric from the outer wrap of the roll or the inner wraparound the core of the roll of fabric.7.3 Test SpecimensFrom each laboratory sampling unit,take five specimens from the machine direction and fivespecim
36、ens from the cross-machine direction, for each testcondition described in 9.1 and 9.2, as applicable to a materialspecification or contract order.7.3.1 Direction of TestConsider the long direction as thedirection of test.7.3.2 Cutting Test SpecimensTake the specimens to beused for the measurement of
37、 machine direction with the longerdimension parallel to the machine direction. Take the speci-mens to be used for the measurement of the cross-machinedirection with the longer dimension parallel to the cross-machine direction. When specimens are to be tested wet, takethe specimens from areas adjacen
38、t to the dry test specimens.Label to maintain specimen identity.7.3.2.1 In cutting the woven fabric specimens, take care toalign the yarns running in the short direction parallel with thedie such that when the slit is cut, the subsequent tear will takeplace between these yarns and not across them. T
39、his precautionis most important when testing bowed fabrics.7.3.2.2 Cut specimens representing a broad distributionacross the width and length, preferably along the diagonal ofthe laboratory sample, and no nearer the edge than one tenth itswidth. Ensure specimens are free of folds, creases, or wrinkl
40、es.Avoid getting oil, water, grease, and so forth, on the specimenswhen handling.7.3.2.3 Use the cutting die or template described in 6.3 andshown in Fig. 2. Mark each specimen with an isoscelestrapezoid template (see Fig. 2). Make a preliminary cut 15 mm(0.625 in.) long at the center of the 25-mm (
41、1-in.) edge, asshown in Fig. 2.NOTE 2Tests were carried out in 2007 to evaluate whether thespecimen size and clamps separation could be increased to facilitate easierloading of the specimen. It was found that this caused a difference in thefinal results depending on the fabric type. Therefore, it is
42、 not possible toincrease the specimen size.8. Preparation of Test Apparatus and Calibration8.1 Set the distance between the clamps at the start of thetest at 25 6 1mm(16 0.05 in.).8.2 Select the full-scale force range of the testing machinesuch that the maximum force occurs between 15 and 85 % offul
43、l-scale force.FIG. 2 Templates for Cutting and Marking Trapezoid Test SpecimensTABLE 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 maximum of 10 rolls or piecesD5587 1
44、438.3 Set the testing speed to 300 6 10 mm (12 6 0.5in./min).8.4 Verify calibration of the tensile testing machine asspecified in the manufacturers instructions and SpecificationD76.8.5 When using microprocessor automatic data gatheringsystems, set the appropriate parameters as specified in themanuf
45、acturers instructions.9. Conditioning9.1 Condition 1, for Standard Testing:9.1.1 Precondition the specimens by bringing them to ap-proximate moisture equilibrium in the standard atmosphere forpreconditioning textiles as specified in Practice D1776, unlessotherwise specified in a material specificati
46、on or contract order.In addition to conditioning, fabric with stretch characteristicsmust be allowed to relax for a period of 24 h prior to samplepreparation.9.1.2 After preconditioning, bring the test specimens tomoisture equilibrium for testing in the standard atmosphere fortesting textiles as spe
47、cified in Practice D1776 or, if applicable,in the specified atmosphere in which the testing is to beperformed, unless otherwise directed in a material specificationor contract order.9.2 Condition 2, for Wet Specimen Testing:9.2.1 Submerge the specimen in a container of distilled ordeionized water at
48、 ambient temperature until thoroughlysoaked.9.2.1.1 The time of immersion must be sufficient to wet outthe specimens, as indicated by no significant change in tearingforce followed by longer periods of immersion. For mostfabrics, this time period will be approximately 1 h. For fabricsnot readily wet
49、 out with water, such as those treated withwater-repellent or water-resistant materials, add a 0.1% solu-tion of a nonionic wetting agent to the water bath.9.2.2 When a desizing treatment is to be performed prior towet testing, use one of the treatments specified in Test MethodsD629. If desized specimens are to be tested wet, follow thesteps in and 9.2.1.1. If desized specimens are to be tested in theconditioned state, follow the steps in 9.1.1 and 9.1.2.9.2.2.1 The time of immersion must be sufficient to wet outthe specimens, as indicated by no significant change in te
