1、Designation: D 1424 07Standard Test Method forTearing Strength of Fabrics by Falling-Pendulum Type(Elmendorf) Apparatus1This standard is issued under the fixed designation D 1424; 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the
3、 determination of the forcerequired to propagate a single-rip tear starting from a cut in afabric and using a falling-pendulum type (Elmendorf) appara-tus.1.2 This test method applies to most fabrics includingwoven, layered blankets, napped pile, blanket, and air bagfabrics, provided the fabric does
4、 not tear in the directioncrosswise to the direction of the force application during thetest. The fabrics may be untreated, heavily sized, coated,resin-treated, or otherwise treated. Instructions are provided fortesting specimens with, or without, wetting.1.3 This method is suitable only for the war
5、p direction testsof warp-knit fabrics. It is not suited for the course direction ofwarp knit fabrics or either direction of most other knittedfabrics.1.4 The values stated in either SI units or U.S. customaryunits are to be regarded as standard, but must be usedindependently of each other. The U.S.
6、customary units may beapproximate.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 applica-bility of regulatory limita
7、tions prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 629 Test Methods for Quantitative Analysis of TextilesD 1776 Practice for Conditioning and Testing TextilesD 2904 Practice for Interlaboratory Testing of a Textile TestMethod that Produces Normally
8、Distributed DataD 2906 Practice for Statements on Precision and Bias forTextilesD 4848 Terminology of Force, Deformation and RelatedProperties of Textiles3. Terminology3.1 Definitions:3.1.1 cross-machine direction, CD, nthe direction in theplane of the fabric perpendicular to the direction of manufa
9、c-ture.3.1.1.1 DiscussionThe term cross-machine direction isused to refer to the direction analogous to coursewise or fillingdirection in woven fabrics, respectively.3.1.2 length of tear, nin tear testing of fabrics, themeasured distance propagated in a specimen by a tearing forcefrom the initiation
10、 of the test to the termination of the test.3.1.3 machine direction, MD, nthe direction in the planeof the fabric parallel to the direction of manufacture.3.1.3.1 DiscussionThe term machine direction is used torefer to the direction analogous to walewise or warp directionin woven fabrics, respective
11、ly.3.1.4 tearing energy, nthe work done in tearing a mate-rial.3.1.5 tearing force, nin fabric, the force applied to propa-gate a tear initiated under specified conditions.3.1.6 tear resistance, nin textiles, the resistance to atearing force.3.1.7 tearing strength, nin fabrics, the force required to
12、propagate a tear after its initiation.3.1.8 fabric, nin textiles, a planar structure consisting ofyarns or fibers.3.1.9 For definitions of other textile terms used in this testmethod, refer to Terminology D 123. For definitions of otherterms related to force and deformation in textiles, refer toTerm
13、inology D 4848.1This 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 July 1, 2007. Published August 2007. Originallyapproved in 1956. Discontinued January 1995 and
14、reinstated as D 1424 96. Lastprevious edition approved in 2004 as D 142496(2004).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
15、 onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 A slit is centrally precut in a test specimen held betweentwo clamps and the specimen is torn through a fixed distance.The resistance to
16、 tearing is in part factored into the scalereading of the instrument and is computed from this readingand the pendulum capacity.5. Significance and Use5.1 This test method for the determination of tearingstrength by the falling pendulum type apparatus is used in thetrade for the acceptance testing o
17、f commercial shipments offabrics, but caution is advised since technicians may fail to getgood agreement between results on certain fabrics. Compara-tive tests as directed in 5.1.1 may be needed.5.1.1 In case of a dispute arising from differences inreported test results when using this test method f
18、or acceptancetesting of commercial shipments, the purchaser and the sup-plier should conduct comparative tests to determine if there isa statistical bias between their laboratories. Statistical assis-tance is recommended for the investigation of bias. As aminimum, the two parties should take a group
19、 of test speci-mens that are as homogeneous as possible and that are from alot of fabric of the type in question. The test specimens shouldthen be randomly assigned in equal numbers to each laboratoryfor testing. The average results from the two laboratoriesshould be compared using appropriate stati
20、stical analysis andan acceptable probability level chosen by the two parties beforethe testing began. If a bias is found, either its cause must befound and corrected or the purchaser and the supplier mustagree to interpret future test results with consideration to theknown bias.5.2 Microprocessor sy
21、stems for automatic collection of datacan provide economical and reliable results when properlycalibrated.6. Apparatus6.1 Falling-Pendulum (Elmendorf) Type Tester3The testerincludes: a stationary clamp, a clamp carried on a pendulumthat is free to swing on a bearing, means for leveling asapplicable,
22、 means for holding the pendulum in a raisedposition, means for instantly releasing the pendulum, andmeans for measuring the force to tear the test specimen.6.1.1 A knife can be mounted on a stationary post for initialslitting of the specimens centered between the clamps andadjusted in height to give
23、 a tearing distance of 43.0 6 0.15 mm(1.69 6 0.005 in.); that is, the distance between the end of theslit made by the knife and the upper edge of the specimen is43.0 6 0.15 mm (1.69 6 0.005 in.) when the lower edge of the63.0-mm (2.5 6 0.005 in.) wide specimen rests against thebottom of the clamp.6.
24、1.2 With the pendulum in its initial position ready for atest, the two clamps are separated by a distance of 2.5 6 0.25mm (0.1 6 0.01 in.) and are aligned such that the clampedspecimen lies in a plane parallel to the axis of the pendulum,the plane making an angle of 0.480 rad (27.5 6 0.5) with thepe
25、rpendicular line joining the axis and the horizontal lineformed by the top edges of the clamping jaws. The distancebetween the axis and the top edges of the clamping jaws is1036 0.1 mm (4.055 6 0.004 in.). The clamping surface ineach jaw is at least 25 mm (1.0 in.) wide and 15.9 6 0.1 mm(0.625 6 0.0
26、04 in.) deep.6.1.3 The tester may have a pointer mounted on the sameaxis as the pendulum to register the tearing force, or it may besubstituted by means of calculating and displaying the requiredresults without the use of a pointer, such as digital display andcomputer driven systems. Preferably the
27、clamps may be airactuated, but manual clamping is permitted.6.1.4 The test instrument should be equipped to provideinterchangeable full scale force ranges. Typical full scaleranges are shown in Table A3.1.6.2 Calibration Weight(s) for graduation of 50 % of the fullscale force range, or other means a
28、s described by the manu-facturer of the test apparatus.6.3 Cutting Die having essentially the shape and dimen-sions shown in Fig. 1(a) or (b). Either die provides the basicrectangular test specimen 100 6 2mm(46 0.05 in.) long by63 6 0.15 mm (2.5 6 0.005 in.) wide, along with additionalfabric at the
29、top edge of the specimen to help ensure the bottomportion of specimen will be torn during the test. The criticaldimension of the test specimen is the distance 43.0 6 0.15 mm(1.696 0.005 in.) which is to be torn during the test.NOTE 1The improved die model shown in Fig. 1(a) has two newfeatures not f
30、ound in the original model, Fig. 1(b), namely a cutout for thebottom of the specimen to aid in centering it in the clamps, and (optional)provision for cutting the 20.0 mm (0.75 in.) slit prior to inserting thespecimen in the tester. These dies can be made to order by most diemanufacturers.6.4 Air Pr
31、essure Regulator, capable of controlling gage airpressure between 410 kPa and 620 kPa (60 psi and 90 psi),when applicable, for air clamps.6.5 Setting Gage for Cutting Blade that will provide a cutslit that leaves a 43 6 0.15 mm (1.69 6 0.005 in.) specimentearing distance for a 63 6 0.15 mm (2.5 6 0.
32、005 in.) widespecimen, or equivalent.6.6 Jaw Spacing Gage 2.5 6 0.25 mm (0.1 6 0.01 in.)width, or equivalent.6.7 Oil, light weight, non-gumming clock type.6.8 Silicone Grease, when applicable, for air clamp lubri-cation.6.9 Vacuum Cleaner, when applicable, for cleaning dust andfiber from sensor, or
33、equivalent.3Apparatus is commercially available. FIG. 1 Die Diagram for Cutting Notched SpecimensD14240727. 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 applicable material specification or other
34、 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 rollsor pieces specified in Table 1.NOTE 2An adequate specification or other agreement between thepurchaser and supp
35、lier 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 limiting quality level.7.2 Laboratory SampleF
36、or 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 roll or the inner wraparound the core of the r
37、oll of fabric.7.3 Test SpecimensFrom each laboratory sampling unit,take five specimens from the machine direction and 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 TestCon
38、sider the long direction of thespecimen as the direction of test.7.3.2 Cutting Test SpecimensTake the specimens to beused for the measurement of machine direction with the longerdimension parallel to the machine direction. Take the speci-mens to be used for the measurement of the cross-machine witht
39、he longer dimension parallel to the cross-machine direction.Use the cutting die described in 6.3 and shown in Fig. 1(a) or(b), as applicable. When specimens are to be tested wet, cutfrom areas adjacent to the dry test specimens. Label tomaintain specimen identity.7.3.2.1 In cutting the woven fabric
40、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. This precautionis most important when testing bowed fabrics.7.3.2.2 Cut specimens representing a broa
41、d distributionacross the width and length, and preferably along the diagonalof the laboratory sample, and no nearer the edge than one-tenthits width. Ensure specimens are free of folds, creases, orwrinkles.Avoid getting oil, water, grease, etc. on the specimenswhen handling.NOTE 3The reading obtaine
42、d is directly proportional to the length ofthe material torn, therefore, it is essential that the specimen be prepared tothe exact size specified.8. Preparation of Apparatus and Calibration8.1 Select test instrument force range, such that the tearoccurs between 20 and 80 % or 20 and 60 % of the full
43、-scalerange as applicable. Ensure the clamps are spaced as directedin A1.4.NOTE 4For standard test apparatus, the useable portion of the fullscale force range is 20 to 80 %. For the high capacity test instrument, theuseable portion of the full scale force range is 20 to 60 %.8.2 When equipped with a
44、 registering sensor, examine thescale and the complementary sensor, as applicable. Using careand without touching the sensor, vacuum away any loose fibersand dust.8.3 Examine the knife edge for sharpness, wear, and centralalignment as directed in A1.5-A1.7.8.4 For air clamps, set the air gage pressu
45、re to the clamps toabout 550 kPa (80 psi).8.4.1 Maximum gage pressure should be no more than 620kPa (90 psi) and minimum gage pressure no less than 410 kPa(60 psi).8.5 When using microprocessor automatic data gatheringsystems, set the appropriate parameters as defined in themanufacturers instruction
46、s.8.6 Verify the calibration of the selected pendulum full scaleforce range using the procedure described in Annex A2, unlessotherwise specified.9. Conditioning9.1 Condition 1, Standard Testing Conditioning:9.1.1 Precondition the specimens by bringing them to ap-proximate moisture equilibrium in the
47、 standard atmosphere forpreconditioning textiles as directed in Practice D 1776, unlessotherwise directed 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 directed
48、in Practice 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.9.2 Condition 2, Wet Specimen Testing Conditioning:9.2.1 When desizing treatments are specified prior to wettesting, use des
49、izing treatments that will not affect the normalphysical property of the fabric as directed in Test MethodD 629.9.2.2 Submerge the specimens in a container of distilled ordeionized water at ambient temperature until thoroughlysoaked (see 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 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 re
