1、Designation: D 5587 07Standard Test Method forTearing Strength of Fabrics by Trapezoid Procedure1This standard is issued under the fixed designation D 5587; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 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 the measurement of the tearingstrength of textile fabrics by the trapezoid procedure using arecording const
3、ant-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.Consequent
4、ly, 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, knittedfabric
5、s, layered fabrics, and pile fabrics. The fabrics may beuntreated, heavily sized, coated, resin-treated, or otherwisetreated. Instructions are provided for testing specimens with orwithout wetting.1.3 Tearing strength, as measured in this test method,requires that the tear be initiated before testin
6、g. 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 thestandard
7、. 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 applica-bil
8、ity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD 123 Terminology Relating to TextilesD 629 Test Methods for Quantitative Analysis of TextilesD 1776 Practice for Conditioning and Testing TextilesD 2904 P
9、ractice for Interlaboratory Testing of a Textile TestMethod that Produces Normally Distributed DataD 2906 Practice for Statements on Precision and Bias forTextilesD 4850 Terminology Relating to Fabric3. Terminology3.1 For definitions of textile terms used in this test method,fabric, in textiles; pea
10、k force, in tear testing of fabrics; tearingforce, in fabric; tearing strength, in fabrics, refer to Terminol-ogy D 4850.3.2 For other textile terms used in this test method, refer toTerminology D 123.4. Summary of Test Method4.1 An outline of an isosceles trapezoid is marked on arectangular specime
11、n (see Fig. 1). The specimen is slit at thecenter of the smallest base of the trapezoid to start the tear. Thenonparallel sides of the marked trapezoid are clamped inparallel jaws of a tensile testing machine. The separation of thejaws is increased continuously to apply a force to propagate thetear
12、across the specimen.At the same time, the force developedis recorded. The force to continue the tear is calculated fromautographic chart recorders or microprocessor data collectionsystems.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of
13、 Subcommittee D13.60 on Fabric Test Methods,Specific.Current edition approved July 1, 2007. Published August 2007. Originallyapproved in 1996. Last previous edition approved in 2005 as D 5587 05.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
14、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 This test method is cons
15、idered satisfactory for accep-tance testing 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
16、 laboratories (or more), comparative testshould 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
17、 that resulted in disparate results duringinitial 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, a probability level chosen prior to the testingseries. If bias is fo
18、und, either its cause must be found andcorrected, 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 estim
19、ating the relative tearresistance of different 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, i
20、ndividually or in combination, neededto stop 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
21、modification of clamping techniques may be 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.5.6 The CRE-type is t
22、he preferred tensile testing machine.This test method 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, the
23、se two tensile testerscannot be used interchangeably 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 Machine3, of the CRE-type conformingto the requirements of
24、Specification D76 with autographicrecorder, or automatic microprocessor data gathering system.6.2 Clamps, having all gripping surfaces parallel, flat, andcapable of preventing slipping of the specimen during a test,and measuring at least 50 by 75 mm (at least 2 by 3 in.), withthe longer dimension pe
25、rpendicular to the direction of appli-cation of the force.6.2.1 The use of hydraulic pneumatic clamping systemswith a minimum of 50 by 75-mm (2 by 3-in.) serrated or rubberjaw faces having a clamping force at the grip faces of 13 to 14kN (2900 to 3111 lbf) is recommended. Manual clamping ispermitted
26、 providing no slippage of the specimen is observed.6.2.2 For some fabrics, to prevent slippage when using jawfaces other than serrated, such as rubber-faced jaws, the jawfaces may be covered with a No. 80 to 120 medium-grit emerycloth. Secure the emery cloth to the jaw faces with pressure-sensitive
27、tape.6.3 Cutting Die or Template, having essentially the shapeand dimensions shown in Fig. 1a.6.4 Trapezoid-Shaped Template, having dimensions asshown in Fig. 1b.7. Sampling and Test Specimens7.1 Lot SampleAs a lot sample for acceptance testing,randomly select the number of rolls or pieces of fabric
28、 directedin 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 1An adequate specification o
29、r other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween rolls or pieces of fabric and between specimens from a swatch3Apparatus and accessories are commercially available.(a)(b)FIG. 1 Templates for Cutting and Marking Trapezoid TestSpecimensD558707
30、2from a roll 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 di
31、rection from 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
32、fivespecimens 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 meas
33、urement of 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 are
34、as adjacent 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 acro
35、ss them. This 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,
36、 or wrinkles.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. 1. Mark each specimen with an isoscelestrapezoid template (see Figs. 1 and 2). Make a preliminary cut15 mm (0.625 in.) long at the cent
37、er of the 25-mm (1-in.) edge,as shown in Figs. 1 and 2.8. 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 an
38、d 85 % offull-scale force.8.3 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
39、as specified in themanufacturers 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 D 1776, unlessotherwise specified
40、in a material specification or contract order.9.1.2 After preconditioning, bring the test specimens tomoisture equilibrium for testing in the standard atmosphere fortesting textiles as specified in Practice D 1776 or, if applicable,in the specified atmosphere in which the testing is to beperformed,
41、unless otherwise directed in a material specificationor contract order.9.2 Condition 2, for Wet Specimen Testing:9.2.1 When desizing treatments are specified prior to wettesting, use desizing treatments that will not affect the normalphysical property of the fabric as specified in Test MethodD 629.9
42、.2.2 Submerge the specimens in a container of distilled ordeionized water at ambient temperature until thoroughlysoaked (see section 8.2.1.1).9.2.2.1 The time of immersion must be sufficient to wet outthe specimens, as indicated by no significant change in tearingforce followed by longer periods of
43、immersion. For mostfabrics this time period will be about 1 h. For fabrics notreadily wet out with water, such as those treated with water-repellent or water-resistant materials, add a 0.1 % solution of anonionic wetting agent to the water bath.10. Procedure10.1 Test the conditioned specimens in the
44、 standard atmo-sphere for testing textiles, which is 21 6 1C (70 6 2F) and65 6 2 % relative humidity, unless otherwise specified in amaterial specification or contract order.10.2 Secure the test specimen in the machine, clampingalong the nonparallel sides of the trapezoid such that the endedges of t
45、he clamps are in line with the 25-mm (1-in.) long sideof the trapezoid, and the cut is halfway between the clamps.Hold the short edge taut, and let the remaining fabric lie infolds.TABLE 1 Number of Rolls or Pieces of Fabric in the Lot SampleNumber of Rolls or Piecesin Lot, InclusiveNumber of Rolls
46、or Pieces in Lot Sample1to3 all4to24 425 to 50 5over 50 10 % to a maximum of 10 rolls or piecesFIG. 2 Diagram of Marked Trapezoid SpecimenD558707310.2.1 For wet testing, remove a specimen from the water,and immediately mount it on the testing machine in the normalsetup. Perform the test within 2 min
47、 after removal of thespecimen from the water. If more than 2 min elapse betweentaking the wet specimen from the water bath and starting thetension testing machine, discard the specimen and take another.10.3 Start the machine and record the tearing force on therecording device. The tearing force may
48、increase to a simplemaximum value or may show several maxima and minima, asshown in Fig. 3.10.4 After the crosshead has moved to produce approxi-mately 6 mm (0.25 in.) of fabric tear, record the single-peakforce or multiple-peak forces as indicated for the type fabricand tearing action observed. Sto
49、p the crosshead motion after atotal tear of approximately 75 mm (3 in.) or the fabric has torncompletely, and return the crosshead to its starting position.10.4.1 If a fabric slips in the jaws or if 25 % or more of thespecimens break at a point within 5 mm (0.25 in.) of the edgeof the jaw, then the jaws may be padded, the fabric may becoated under the jaw face area, or the jaw face may bemodified. If any of these modifications are used, state themethod of modification in the report.NOTE 2Due to dense fabric construction, weave derivations, yarnstrengths or combinations o
