StandardTestMethodfor
TearingStrengthofFabricsbyFalling-Pendulum(Elmendorf-Type)Apparatus1ThisstandardisissuedunderthefixeddesignationD1424;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.
1.Scope
1.1Thistestmethodcoversthedeterminationoftheforcerequiredtopropagateasingle-riptearstartingfromacutinafabricandusingafalling-pendulum(Elmendorf-Type)appa-ratus.
1.2Thistestmethodappliestomostfabricsincludingwoven,layeredblankets,nappedpile,blanket,andairbagfabrics,providedthefabricdoesnottearinthedirectioncrosswisetothedirectionoftheforceapplicationduringthetest.Thefabricsmaybeuntreated,heavilysized,coated,resin-treated,orotherwisetreated.Instructionsareprovidedfortestingspecimenswith,orwithout,wetting.
1.3Thistestmethodissuitableonlyforthewarpdirectiontestsofwarp-knitfabrics.Itisnotsuitedforthecoursedirectionofwarpknitfabricsoreitherdirectionofmostotherknittedfabrics.
1.4ThevaluesstatedineitherSIunitsorU.S.customaryunitsaretoberegardedasstandard,butmustbeusedindependentlyofeachother.TheU.S.customaryunitsmaybeapproximate.
1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.
2.ReferencedDocuments2.1ASTMStandards:2D123TerminologyRelatingtoTextiles
D629TestMethodsforQuantitativeAnalysisofTextilesD1776PracticeforConditioningandTestingTextilesD2261TestMethodforTearingStrengthofFabricsbythe
Tongue(SingleRip)Procedure(Constant-Rate-of-ExtensionTensileTestingMachine)
D2904PracticeforInterlaboratoryTestingofaTextileTestMethodthatProducesNormallyDistributedData
D2906PracticeforStatementsonPrecisionandBiasforTextiles3D4848TerminologyRelatedtoForce,DeformationandRelatedPropertiesofTextiles
D4850TerminologyRelatingtoFabricsandFabricTestMethods
D5587TestMethodforTearingStrengthofFabricsbyTrapezoidProcedure
3.Terminology
3.1ForallterminologyrelatingtoD13.59,FabricTestMethods,General,refertoTerminologyD4850.
3.2ForallterminologyrelatingtoForce,DeformationandRelatedPropertiesinTextiles,refertoTerminologyD4848.3.2.1Thefollowingtermsarerelevanttothisstandard:cross-machinedirection,CD,lengthoftear,machinedirection,MD,tearingenergy,tearingforce,tearresistance,tearingstrength,fabric.
3.3Forallotherterminologyrelatedtotextiles,refertoTerminologyD123.
4.SummaryofTestMethod
4.1Aslitiscentrallyprecutinatestspecimenheldbetweentwoclampsandthespecimenistornthroughafixeddistance.Theresistancetotearingisinpartfactoredintothescalereadingoftheinstrumentandiscomputedfromthisreadingandthependulumcapacity.
5.SignificanceandUse
5.1Thistestmethodforthedeterminationoftearingstrengthbythefallingpendulumtypeapparatusisusedinthetradefortheacceptancetestingofcommercialshipmentsoffabrics,butcautionisadvisedsincetechniciansmayfailtogetgoodagreementbetweenresultsoncertainfabrics.Compara-tivetestsasdirectedin5.1.1maybeneeded.
Withdrawn.Thelastapprovedversionofthishistoricalstandardisreferencedonwww.astm.org.
3ThistestmethodisunderthejurisdictionofASTMCommitteeD13onTextilesandisthedirectresponsibilityofSubcommitteeD13.60onFabricTestMethods,Specific.
CurrenteditionapprovedJan.15,2009.PublishedJanuary2009.Originallyapprovedin1956.DiscontinuedJanuary1995andreinstatedasD1424–96.Lastpreviouseditionapprovedin2007asD1424–07a.2ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.
1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.
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D1424–09
5.1.1Incaseofadisputearisingfromdifferencesinreportedtestresultswhenusingthistestmethodforacceptancetestingofcommercialshipments,thepurchaserandthesup-pliershouldconductcomparativeteststodetermineifthereisastatisticalbiasbetweentheirlaboratories.Statisticalassis-tanceisrecommendedfortheinvestigationofbias.Asaminimum,thetwopartiesshouldtakeagroupoftestspeci-mensthatareashomogeneousaspossibleandthatarefromalotoffabricofthetypeinquestion.Thetestspecimensshouldthenberandomlyassignedinequalnumberstoeachlaboratoryfortesting.Theaverageresultsfromthetwolaboratoriesshouldbecomparedusingappropriatestatisticalanalysisandanacceptableprobabilitylevelchosenbythetwopartiesbeforethetestingbegan.Ifabiasisfound,eitheritscausemustbefoundandcorrectedorthepurchaserandthesuppliermustagreetointerpretfuturetestresultswithconsiderationtotheknownbias.
5.2Microprocessorsystemsforautomaticcollectionofdatacanprovideeconomicalandreliableresultswhenproperlycalibrated.SeeTestMethodsD2261andD5587.
6.Apparatus
6.1Falling-Pendulum(Elmendorf-Type)Tester4—Thetesterincludes:astationaryclamp,aclampcarriedonapendulumthatisfreetoswingonabearing,meansforlevelingasapplicable,meansforholdingthependuluminaraisedposition,meansforinstantlyreleasingthependulum,andmeansformeasuringtheforcetotearthetestspecimen.
6.1.1Aknifecanbemountedonastationarypostforinitialslittingofthespecimenscenteredbetweentheclampsandadjustedinheighttogiveatearingdistanceof43.060.15mm(1.6960.005in.);thatis,thedistancebetweentheendoftheslitmadebytheknifeandtheupperedgeofthespecimenis43.060.15mm(1.6960.005in.)whentheloweredgeofthe63.0-mm(2.560.005in.)widespecimenrestsagainstthebottomoftheclamp.
6.1.2Withthependuluminitsinitialpositionreadyforatest,thetwoclampsareseparatedbyadistanceof2.560.25mm(0.160.01in.)andarealignedsuchthattheclampedspecimenliesinaplaneparalleltotheaxisofthependulum,theplanemakinganangleof0.480rad(27.560.5°)withtheperpendicularlinejoiningtheaxisandthehorizontallineformedbythetopedgesoftheclampingjaws.Thedistancebetweentheaxisandthetopedgesoftheclampingjawsis10360.1mm(4.05560.004in.).Theclampingsurfaceineachjawisatleast25mm(1.0in.)wideand15.960.1mm(0.62560.004in.)deep.
6.1.3Thetestermayhaveapointermountedonthesameaxisasthependulumtoregisterthetearingforce,oritmaybesubstitutedbymeansofcalculatinganddisplayingtherequiredresultswithouttheuseofapointer,suchasdigitaldisplayandcomputerdrivensystems.Preferablytheclampsmaybeairactuated,butmanualclampingispermitted.
6.1.4Thetestinstrumentshouldbeequippedtoprovideinterchangeablefullscaleforceranges.TypicalfullscalerangesareshowninTableA3.1.
46.2CalibrationWeight(s)forgraduationof50%ofthefullscaleforcerange,orothermeansasdescribedbythemanu-facturerofthetestapparatus.
6.3CuttingDiehavingessentiallytheshapeanddimen-sionsshowninFig.1(a)or(b).Eitherdieprovidesthebasicrectangulartestspecimen10062mm(460.05in.)longby6360.15mm(2.560.005in.)wide,alongwithadditionalfabricatthetopedgeofthespecimentohelpensurethebottomportionofspecimenwillbetornduringthetest.Thecriticaldimensionofthetestspecimenisthedistance43.060.15mm(1.6960.005in.)whichistobetornduringthetest.
NOTE1—TheimproveddiemodelshowninFig.1(a)hastwonewfeaturesnotfoundintheoriginalmodel,Fig.1(b),namelyacutoutforthebottomofthespecimentoaidincenteringitintheclamps,and(optional)provisionforcuttingthe20.0mm(0.75in.)slitpriortoinsertingthespecimeninthetester.Thesediescanbemadetoorderbymostdiemanufacturers.
6.4AirPressureRegulator,capableofcontrollinggageairpressurebetween410kPaand620kPa(60psiand90psi),whenapplicable,forairclamps.
6.5SettingGageforCuttingBladethatwillprovideacutslitthatleavesa4360.15mm(1.6960.005in.)specimentearingdistancefora6360.15mm(2.560.005in.)widespecimen,orequivalent.
6.6JawSpacingGage2.560.25mm(0.160.01in.)width,orequivalent.
6.7Oil,lightweight,non-gummingclocktype.
6.8SiliconeGrease,whenapplicable,forairclamplubri-cation.
6.9VacuumCleaner,whenapplicable,forcleaningdustandfiberfromsensor,orequivalent.
7.SamplingandTestSpecimens
7.1LotSample—Asalotsampleforacceptancetesting,randomlyselectthenumberofrollsorpiecesoffabricdirectedinanapplicablematerialspecificationorotheragreementbetweenthepurchaserandthesupplier.Considertherollsorpiecesoffabrictobetheprimarysamplingunits.Intheabsenceofsuchanagreement,takethenumberoffabricrollsorpiecesspecifiedinTable1.
NOTE2—Anadequatespecificationorotheragreementbetweenthepurchaserandsupplierrequirestakingintoaccountthevariabilitybetweenrollsorpiecesoffabricandbetweenspecimensfromaswatchfromarollorpieceoffabrictoprovideasamplingplanwithameaningfulproducer’srisk,consumer’srisk,acceptablequalitylevel,andlimitingqualitylevel.
Apparatusiscommerciallyavailable.FIG.1DieDiagramforCuttingNotchedSpecimens
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D1424–09
TABLE1NumberofRollsorPiecesofFabricintheLotSample
NumberofRollsorPieces
inLot,Inclusive
1to34to2425to50over50
NumberofRollsorPiecesinLot
Sampleall45
10%toamaxof10rollsorpieces
7.2LaboratorySample—Foracceptancetesting,takeaswatchextendingthewidthofthefabricandapproximately1m(1yd)alongthemachinedirectionfromeachrollorpieceinthelotsample.Forrollsoffabric,takeasamplethatwillexcludefabricfromtheouterwrapoftherollortheinnerwraparoundthecoreoftherolloffabric.
7.3TestSpecimens—Fromeachlaboratorysamplingunit,takefivespecimensfromthemachinedirectionandfivespecimensfromthecross-machinedirection,foreachtestconditiondescribedin9.1and9.2,asapplicabletoamaterialspecificationorcontractorder.
7.3.1DirectionofTest—Considerthelongdirectionofthespecimenasthedirectionoftest.
7.3.2CuttingTestSpecimens—Takethespecimenstobeusedforthemeasurementofmachinedirectionwiththelongerdimensionparalleltothemachinedirection.Takethespeci-menstobeusedforthemeasurementofthecross-machinewiththelongerdimensionparalleltothecross-machinedirection.Usethecuttingdiedescribedin6.3andshowninFig.1(a)or(b),asapplicable.Whenspecimensaretobetestedwet,cutfromareasadjacenttothedrytestspecimens.Labeltomaintainspecimenidentity.
7.3.2.1Incuttingthewovenfabricspecimens,takecaretoaligntheyarnsrunningintheshortdirectionparallelwiththediesuchthatwhentheslitiscut,thesubsequenttearwilltakeplacebetweentheseyarnsandnotacrossthem.Thisprecautionismostimportantwhentestingbowedfabrics.
7.3.2.2Cutspecimensrepresentingabroaddistributionacrossthewidthandlength,andpreferablyalongthediagonalofthelaboratorysample,andnonearertheedgethanone-tenthitswidth.Ensurespecimensarefreeoffolds,creases,orwrinkles.Avoidgettingoil,water,grease,etc.onthespecimenswhenhandling.
NOTE3—Thereadingobtainedisdirectlyproportionaltothelengthofthematerialtorn,therefore,itisessentialthatthespecimenbepreparedtotheexactsizespecified.
8.3Examinetheknifeedgeforsharpness,wear,andcentralalignmentasdirectedinA1.5-A1.7.
8.4Forairclamps,settheairgagepressuretotheclampstoabout550kPa(80psi).
8.4.1Maximumgagepressureshouldbenomorethan620kPa(90psi)andminimumgagepressurenolessthan410kPa(60psi).
8.5Whenusingmicroprocessorautomaticdatagatheringsystems,settheappropriateparametersasdefinedinthemanufacturer’sinstructions.
8.6VerifythecalibrationoftheselectedpendulumfullscaleforcerangeusingtheproceduredescribedinAnnexA2,unlessotherwisespecified.9.Conditioning
9.1Condition1,StandardTestingConditioning:
9.1.1Preconditionthespecimensbybringingthemtoap-proximatemoistureequilibriuminthestandardatmosphereforpreconditioningtextilesasdirectedinPracticeD1776,unlessotherwisedirectedinamaterialspecificationorcontractorder.9.1.2Afterpreconditioning,bringthetestspecimenstomoistureequilibriumfortestinginthestandardatmospherefortestingtextilesasdirectedinPracticeD1776or,ifapplicable,inthespecifiedatmosphereinwhichthetestingistobeperformed,unlessotherwisedirectedinamaterialspecificationorcontractorder.
9.2Condition2,WetSpecimenTestingConditioning:
9.2.1Whendesizingtreatmentsarespecifiedpriortowettesting,usedesizingtreatmentsthatwillnotaffectthenormalphysicalpropertyofthefabricasdirectedinTestMethodD629.
9.2.2Submergethespecimensinacontainerofdistilledordeionizedwateratambienttemperatureuntilthoroughlysoaked(see8.2.1.1).
9.2.2.1Thetimeofimmersionmustbesufficienttowetoutthespecimens,asindicatedbynosignificantchangeintearingforcefollowedbylongerperiodsofimmersion.Formostfabricsthistimeperiodwillbeabout1h.Forfabricsnotreadilywetoutwithwater,suchasthosetreatedwithwater-repellent,orwaterresistantmaterials,adda0.1%solutionofanonionicwettingagenttothewaterbath.10.Procedure
10.1Testtheconditionedspecimensinthestandardatmo-spherefortestingtextiles,whichis2161°C(7062°F)and6562%relativehumidity,unlessotherwisedirectedinamaterialspecificationorcontractorder.
10.2Positionthependulumtothestartingpositionandtheforcerecordingmechanismtoitszero-forceposition.10.3ForTester-SlitSpecimens:
10.3.1Placethelongsidesofthespecimencentrallyintheclampswiththebottomedgecarefullysetagainstthestopsandtheupperedgeparalleltothetopoftheclamps.Closetheclamps,securingthespecimenwithapproximatelythesametensiononbothclamps.Thespecimenshouldliefreewithitsupperareadirectedtowardthependulumtoensureashearingaction.
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8.PreparationofApparatusandCalibration
8.1Selecttestinstrumentforcerange,suchthatthetearoccursbetween20and80%or20and60%ofthefull-scalerangeasapplicable.EnsuretheclampsarespacedasdirectedinA1.4.
NOTE4—Forstandardtestapparatus,theuseableportionofthefullscaleforcerangeis20to80%.Forthehighcapacitytestinstrument,theuseableportionofthefullscaleforcerangeis20to60%.
8.2Whenequippedwitharegisteringsensor,examinethescaleandthecomplementarysensor,asapplicable.Usingcareandwithouttouchingthesensor,vacuumawayanyloosefibersanddust.
D1424–09
10.3.2Usingthebuilt-inknifebladecuta20mm(0.787in.)slitinthespecimenextendingfromthebottomedgeandleavingabalanceoffabric43.060.15mm(1.6960.005in.)remainingtobetorn.
10.4ForDie-CutorManuallySlitSpecimens:
10.4.1Ifadiewithoutaslitisused,manuallycuta20mm(0.787in.)longslitinthecenterofoneedgeofthelongdirectionofthespecimen.Ensurethatthebalanceofthefabricremainingtobetornis4360.15mm(1.6960.005in.).
NOTE5—Thelengthofthecutisimportant,seeNote3.
11.1.1StandardTestInstrument—Determinethetearingforceforindividualspecimenstothenearest1%offull-scalerangeusingEq1.
Ft5Rs3Cs/100
(1)
10.4.2Placetheparallel,unslitsidesofthespecimenintheclampswiththebottomedgecarefullysetagainstthestops,theupperedgeparalleltothetopoftheclampandtheslitcentrallylocatedbetweentheclamps.Closetheclamps,securingthespecimenwithapproximatelythesametensiononbothclamps.Thespecimenshouldliefreewithitsupperareadirectedtowardthependulumtoensureashearingaction.10.5ForWetSpecimenTesting:
10.5.1Removeaspecimenfromthewaterandimmediatelymountitonthetestingmachineinthenormalset-up.Performthetestwithin2minafterremovalofthespecimenfromthewater.Otherwise,discardthespecimenandreplacewithanotherone.
10.6Depressthependulumstopdownwardtoitslimitandholdituntiltheteariscompletedandthependulumhascompleteditsforwardswing.Catchthependulumjustafterthethresholdofitsbackwardswingandreturntoitslockedstartingposition.Whenequipped,becarefulnottodisturbthepositionofthepointer.Recordthescalereadingrequiredtocompletelytearthetestspecimen.
10.6.1Thedecisiontodiscardtheresultsofatearshallbebasedonobservationofthespecimenduringatestandupontheinherentvariabilityofthematerial.Intheabsenceofothercriteria,suchasinamaterialspecification,ifanunusualcauseisdetected,thevaluemaybediscardedandanotherspecimentested.
10.6.2Rejectreadingsobtainedwherethespecimenslipsinthejaworwheretheteardeviatesmorethan6mm(0.25in.)awayfromtheprojectionoftheoriginalslit.Notewhenpuckeringoccursduringthetest.
10.6.3Formicroprocessorsystems,followthemanufactur-er’sdirectionsforremovingvaluesfrommemorywhenthedecisiontodiscardatearvaluehasbeenmade.Otherwise,forsometestinstrumentsmanualcalculationoftheaverageisrequired.
10.6.4If,duringthetest,thescalereadingdoesnotreach20%orreachesover80%(60%whenapplicable,seeTableA3.1)offullscalerange,changetothenextlowerorhigherfullscalerange,asapplicable.See8.6.
10.6.5Recordifthetearwascross-wisetothenormal(parallel)directionoftearandreportthatspecimen,orthatsample,asapplicable,asuntearable.
10.7Removethetornspecimenandcontinueuntilfivetearshavebeenrecordedforeachtestdirectionandtestcondition,asrequired,fromeachlaboratorysamplingunit.11.Calculations
11.1TearingForce,IndividualSpecimens:
4
where:
Ft=tearingforce,cN(gf)orlbf,Rs=scalereading,
Cs=fullscalecapacity,cN(gf)orlbf.
11.1.2HeavyDutyTestInstrument—Determinethetearingforceforindividualspecimenstothenearest1%offull-scalerangeusingEq2.
Ft5Rs3100
(2)
where:
Ft=tearingforce,cN(gf)orlbf,andRs=scalereading,cN(gf)orlbf.
11.2TearingStrength—Calculatethetearingstrengthastheaveragetearingforceforeachtestdirectionandtestingconditionofthelaboratorysamplingunitandforthelot,tothenearest1%offull-scalerangeincN,(gf)orlbf.
11.3StandardDeviationandCoeffıcientofVariation—Calculatewhenrequested.
11.4Computer-ProcessedData—Whendataareautomati-callycomputer-processed,calculationsaregenerallycontainedintheassociatedsoftware.RecordvaluesasreadfromthedirectreadingscaletothenearestmN(gf).Inanyevent,itisrecommendedthatcomputer-processeddatabeverifiedagainstknownpropertyvaluesanditssoftwaredescribedinthereport.12.Report
12.1ReportthattheElmendorftearingstrengthwasdeter-minedasdirectedinTestMethodD1424.Describethefabricorproductsampledandthemethodofsamplingused.
NOTE6—Someinstrumentsmayrequiredifferentcalculationsthanpercentageofscale.Inthosecases,refertomanufacturer’srecommendedcalculations.
12.2Reportthefollowinginformationforeachlaboratorysamplingunitandforthelotasapplicabletoamaterialspecificationorcontractorder.
12.2.1Elmendorftearingstrengthforeachtestdirectionandtestingcondition,asrequested.
12.2.2Conditionoftest(withorwithoutwetting).12.2.3Puckering,ifitoccursduringthetest.
12.2.4Numberoftestsrejectedbecauseofcrosswisetear-ing.
12.2.5Whencalculated,thestandarddeviationorthecoef-ficientofvariation.
12.2.6Forcomputer-processeddata,identifytheprogram(software)used.
12.2.7Make,modelandcapacityoftestingmachine.
12.2.8Typeofclampsused,manualorpneumatic(includ-ingpressure).
12.2.9Anymodificationofthetestmethod.
13.PrecisionandBias
13.1Summary—Incomparingtwoaverages,thedifferencesshouldnotexceedthesingle-operatorprecisionvaluesshowninTable2fortherespectivenumberoftests,andforfabrics
D1424–09
TABLE2ElmendorfTearStrength,g
CriticalDifferencesfortheConditionsNotedAMachineTypeand
MaterialsBStandardMachinePlain,spunyarns,MAT2
NumberofObservationsinEachAverage
125101251012510
HeavyDutyMachineTwill,spunyarns,MAT1
125101251012510
ATABLE3ElmendorfTearStrength,g
ComponentsofVarianceExpressedas
StandardDeviationsBGrandAverage
Single-Within-Between
OperatorLaboratoryLaboratoryComponentComponentComponent
20049194
02152
10940189
Single-OperatorPrecisionWithin-Between-LaboratoryLaboratoryPrecisionPrecision
MachineTypeand
MaterialsA556393249176135956043538380240170405286181128934660418295561397251177
5563932491761461118372557407281224482387317290934660418295653519418378
632495391349184158140133765664595570497406340315128010979709241478122413901379
Plain,spunyarns,MAT4
Plain,cont.fil.yarns,MAT5
StandardMachinePlain,spunyarns,MAT2
Plain,spunyarns,MAT4
Plain,cont.fil.yarns,MAT5
HeavyDutyMachineTwill,spunyarns,MAT1
Plain,spunyarns,MAT3
Denintwill,spunyarns,MAT9
AB187812463190
470751865264
146337202
940120
44316478
See13.2and13.3foradditionalmaterialdescription.
Thesquarerootsofthecomponentsofvariancearebeingreportedtoexpressthevariabilityintheappropriateunitsofmeasureratherthanasthesquaresofthoseunitsofmeasure.
Plain,spunyarns,MAT3
Denintwill,spunyarns,MAT9
Thecriticaldifferenceswerecalculatedusingt=1.960,whichisbasedoninfinitedegreesoffreedom.BSee13.2and13.3foradditionalmaterialdescription.
havingaveragessimilartothoseshowninTable2,in95outof100caseswhenalltheobservationsaretakenbythesamewell-trainedoperatorusingthesamepieceofequipmentandspecimensarerandomlydrawnfromthesampleoffabric.Largerdifferencesarelikelytooccurunderallothercircum-stances.
13.2ElmendorfTearingStrength,StandardEquipment,In-terlaboratoryTestData—Aninterlaboratorytestwasrunin1994–1995inwhichrandomly-drawnsamplesofthreefabricsweretestedineachofelevenlaboratories.TwooperatorsineachlaboratoryeachtestedeightspecimensofeachfabricusingTestMethodD1424.Fouroftheeightspecimensweretestedononedayandfourspecimensweretestedonasecondday.AnalysisofthedatawasconductedusingthePracticeD2904andPracticeD2906.ThecomponentsofvarianceforElmendorftearstrengthexpressedasstandarddeviationswerecalculatedtobethevalueslistedinTable3.Thethreewovenfabrictypeswere:
(1)Material2—S/1016H,2/1basketplainweavesheeting,withspunyarns,
(2)Material4—S/0008H,plainweavesheeting,withspunyarns,
(3)Material5—S/2438,plainweave,oxford,spunyarns.
13.3ElmendorfTearingStrength,HeavyDutyEquipment,InterlaboratoryTestData—Aninterlaboratorytestwasrunin1994inwhichrandomly-drawnsamplesofthreefabricsweretestedinsixlaboratories.TwooperatorsineachlaboratoryeachtestedeightspecimensofeachfabricusingTestMethodD1424.Fouroftheeightspecimensweretestedononedayandfourspecimensweretestedonasecondday.AnalysisofthedatawasconductedusingPracticeD2904andPracticeD2906.ThecomponentsofvarianceforElmendorftearstrengthexpressedasstandarddeviationswerecalculatedtobethevalueslistedinTable3.Thethreewovenfabrictypeswere:
(1)Material1—S/179B,twillweave,withspunyarns,(2)Material3—S/1008H,plainweavesheeting,withspunyarns,
(3)Material9—Denin,twillweave,withspunyarns.13.4Precision—ForthecomponentsofvariancereportedinTable3,twoaveragesofobservedvaluesshouldbeconsideredsignificantlydifferentatthe95%probabilitylevelifthedifferenceequalsorexceedsthecriticaldifferenceslistedinTable2for“Elmendorf”tearstrength.Thereweresufficientdifferencesrelatedtothefabrictypeandstructuretowarrantlistingthecomponentsofvarianceandthecriticaldifferencesseparately.Consequentlynomulti-fabriccomparisonsweremade.
NOTE7—Thetabulatedvaluesofthecriticaldifferencesshouldbeconsideredtobeageneralstatement,particularlywithrespecttobetween-laboratoryprecision.Beforeameaningfulstatementcanbemadeabouttwospecificlaboratories,theamountofstatisticalbias,ifany,betweenthemmustbeestablished,witheachcomparisonbeingbasedonrecentdataobtainedonspecimenstakenfromalotoffabricofthetypebeingevaluatedsoastobeasnearlyhomogeneousaspossibleandthenrandomlyassignedinequalnumberstoeachofthelaboratories.
13.5Bias—ThevalueofElmendorftearstrengthcanonlybedefinedintermsofatestmethod.Withinthislimitation,TestMethodD1424hasnoknownbias.14.Keywords
14.1Elmendorf;fabric;strength;tear
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D1424–09
ANNEXES
(MandatoryInformation)
A1.ADJUSTMENTOFAPPARATUS:USETHEFOLLOWINGINFORMATIONASAPPLICABLE
A1.1InstrumentMounting—Placethetesteronasturdy,levelbench(ortable).Ensurethatthereisnoperceptiblemovementofthetesterbaseorbenchduringtheswingofthependulum.Movementoftheinstrumentduringtheswingingofthependulumisasignificantsourceoferror.
A1.2InstrumentBalance—Leveltheinstrumentsuchthat,withthesectorfree,thelineonthesectorindicatingthatverticalfromthepointofsuspensionisbisectedbytheedgeofthependulumstopmechanism.Verifythisbyholdingdownthependulumstopandallowingthependulumtoswingfree.Whenthependulumcomestorest,thepositioninglineatthecenterofthependulumshouldbedirectlyabovetheedgeofthependulumstop.Align,ifnecessary,byturningthelevelingthumbscrewattheleftendofthetesterbase.
A1.3ClampAlignment—Raisethependulumandpositiontheloweredgeagainstitsstop.Visuallycheckthealignmentoftheclamps.Iftheclampsarenotinalignment,replacethependulumstoporthependulumbearingandshaftassembly,orboth,followingthemanufacturer’sinstructions.
A1.4ClampSpaceSetting,InterchangeablePendulums—Setthejawspacingto2.560.25mm(0.160.01in.).Loosentheshoulderheadscrewontopofthependulumsupport.Withbothclampsintheopenposition,gentlypullthependulumoutuntilthejawspacergagewillfitintothegrips.Gentlypushthependuluminuntilthejawspacergagehasjustenoughclearancetoslideoutthetopoftheclamps.Withthejawspacerinplace,tightentheshoulderheadscrewonthependulumsupport.Removethejawspacergage.
A1.5KnifeSharpness—Checkthesharpnessoftheknifebyinsertingasparespecimenintheclampsandcuttingaslitwiththeknifebladeinthenormalmanner.IftheknifeisdullitwillproduceaV-notchnearthetopofthecutandpushthematerialoutward.Whentheknifeisdeterminedtobedull,sharpenitwitharoughstone,alternately,continuingspecimenknifecuts,untilnoV-notchisobserved.Replacetheknifebladeifnecessary.
A1.6KnifeAlignment—Checkthattheknifepositioniscentrallylocatedbetweentheclamps.Iftheknifecannotbepositionedcentrally,replaceoneoranycombinationof:thependulumbearingandshaftassembly,thecutterhandle,thecutterhandlebearingpin,knifeblade.
A1.7SpecimenTearingDistance—Checkthespecimentearingdistancewiththeknifesettinggage.Placethegageinthestationaryspecimenclampintheusualmannerfortestingfabric.Ensurethegageispositionedwiththewidedimensionupwardsandtheprojectionextendingovertheedgeofthestationaryclampfarenoughsuchthattheknifecanbeadjusted
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tothebottomedgeofthegage.Adjusttheknifepositionsuchthatthehighestpointofthebladejusttouchesthebottomedgeofthegageandthensecureitinplace.Replacetheknifewhenitnolongercanbeadjustedtothegage,oroptionally.
A1.7.1Checkthetearingdistancebyusingthedietocutaspecimenfromcoordinatepapergraduatedinmillimetres.Applyasmallamountofgraphite(fromanordinaryleadpencil)tothecuttingknifeortheedgeofthedieusedforcuttingtheslitsothatwhenthecutismadesomeofthegraphitetransferstothepaper;thisservestocontrastthecutfromtheuncutportionofthepaperandfacilitatesthemea-surement.Makethismeasurementeitherwithaprecisionsteelrulegraduatedin0.2mm(0.01in.)orbetterand,undermagnification,oralternatively,byuseofago-no-gogageavailablefromthemanufactureroftheinstrument.Ifnecessary,adjusttheheightoftheknife.
A1.7.2Donotchangethespecimendimensionstoadjusttheteardistance.
A1.8MainBearingFriction—Clean,oilandadjustthebearing.Raisethependulumtoitscockedposition.Whenequipped,setthepointeragainstitsstop.Pressandholddownthependulumstopandletthependulumswingfreely.Ensurethependulumisfreeswingingandthecalibrationcanbeverified.
A1.9ScaleInspection—Whensoiled,orcalibrationcannotbeattained,cleanthewhiteareaatthebottomofthependulumwithmildsoapandwater.Ensurethemirroreddivisionsofthescalearecleanandfreeofanyforeignmatter.Ensuretheblacksensingstriponthependulumiscleanoffibersandnotscratched.Blowofffibersanddustfromtheblackstripusingalowpressureairnozzle.Whenscratchesareevident,touchupwithflatblackpaintenamel.
A1.10PendulumStopRelease—Checkthependulumorthependulumstopreleaseforanywear,suchasanotch,whenajerkyreleaseisobserved.Adjusttheheightofthependulumstopuntilasmoothreleaseisobtained.Ifasmoothreleasecannotbeobtainedbythisadjustmentthependulumorthependulumstopmayrequirerepairorreplacement.Ifthependulumstopheightischanged,verifyclampalignmentandzeroposition.
A1.11ZeroPointerStop—Operatetheleveledinstrumentseveraltimeswithnothingintheclamps,themovableclampbeingclosed.Ifzeroisnotregistered,adjustthepointerstopuntilthezeroreadingisobtained.Donotchangetheleveltoadjustthezero.
A1.12PointerFriction—Setthepointeratthezeroreadingonthescalebeforereleasingthesector,andaftertherelease,
D1424–09
ensurethatthepointerisnotpushedmorethanthreescaledivisions(4mm)orlessthantwoscaledivisions(2.5mm)beyondthezero.Ifthepointerfrictiondoesnotliebetweentwoandthreedivisions,removethepointer,wipethebearingclean,andapplyatraceofclockoiltothegrooveofthebearing.Reassembleandcheckpointerfriction.Recheckzeroandreadjustthepointerstopifnecessary.
A1.13OilandGrease—Applyaverysmallamountofclockoilinthegrooveofthebearingandsleeveassembly.Donotoiltheflatsurfacesofthebearingandsleeveassembly.Applyasmallamountofsiliconegreasetotheairclampplungerrods.
A2.VERIFICATIONOFPENDULUMFULLSCALEFORCERANGE
A2.1Insomecasesverificationofthescalereadingofthetestinstrumentcanbeaccomplishedbyweighingthependulumweightsfollowingthemanufacturer’sinstructions.Inothercases,theprocedureoutlinedinA2.2hasbeenusedintheindustryforsometestapparatuses.
A2.1.1Forothermethodsofverificationofthescale,refertothemanufacturer’sinstructions.
A2.2Useacalibratedmassforavalueof50%oftheselectedElmendorftesterscale.Eachcapacityscalerequiresitsowncalibratedmass.Forexample,at800gramsofthe1600gramscale.Thecalibratedmassshallbeconstructedsuchthatthemasscanbeinsertedintheclampsinthesamemannerasusedforafabricspecimen.Generallythebulkofthecalibratedmassfacesdownward.
A2.2.1Positionthependuluminitscockedpositionagainstitsstop,setthedigitalreadout,orpointer,tozero(0).
A2.2.2Depressthependulumstopdownwardtoitslimitandholdituntilthependulumhascompleteditsforwardswing.Catchthependulumjustafterthethresholdofitsbackwardswingandreturnittoitslockedstartingposition.Thepointer,orwhenequipped,thedigitalreadoutshouldread00.0.Inanyevent,donotchangetheleveloftheinstrumenttoadjustthezero.(SeeAnnexA1,ifadjustmentisrequired.)A2.2.2.1Forthepointersystem,thepointershouldnotbepushedlessthan2.5mmnormorethan4.0mmbeyondzero.Ifzeroisnotregistered,thepointerstopshouldbeadjusteduntilthezeroreadingisobtained,otherwiseserviceasdirectedinAnnexA1.
A2.2.3Withthependulumintheraisedposition,opentheclampofthependulum,slidethe50%checkweight,generallywiththebulkofthemassdownward,intopositionandfastenitsecurelyintheclamp.
A2.2.4Depressthependulumstopdownwardtoitslimitandholdituntilthependulumhascompleteditsforwardswing.Catchthependulumjustafterthethresholdofitsbackwardswingandreturntoitslockedstartingposition.Thepointer,orwhenequipped,thedigitalreadoutshouldread5060.5%.(SeeAnnexA1,ifadjustmentisrequired.)
A2.2.5Removethe50%calibrationmass,closetheclamp,andwhenequipped,setthepointertozero(0).
A2.2.6Forpointersystem,ifzero(00.0)and50%readingsarenotobtained,cleanandoilbearingandsleeveassemblyasdirectedinA1.12–A1.3.
A2.2.7Fordigitalreadoutsystems,ifzero(00.0)and50%readingsarenotobtained,adjusttheopticalsensorasdirectedbythemanufactureruntilthetargetvaluesof00.0and50%areobtained.
A2.2.8Ifzero(0.00)and50%readingscannotbeobtained,conductmaintenancedescribedinAnnexA1asappropriateuntilthedesignatedreadingsareobtainedandcalibrationisverified.
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D1424–09
A3.TYPICALFULL-SCALERANGESFORELMENDORFTEARTESTERS
SeeTableA3.1.
TABLEA3.1TypicalPendulumFullScaleForceRanges
NOTE1—Heavy-dutycapacityandhighcapacitytermsareusedsyn-onomouslyinthetextileindustry.
ElmendorfTear
Tester
Capacity,
gf
Capacity,cN
UseableTestRange,
gf(cN)
20to80%
StandardStandardStandardStandardStandardStandardStandardStandardStandard
capacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacitycapacity
200400800160032006400.........64001280025600.........
..................150350800.........180042009600
40to16080to320160to640320to1280640to25601280to5120(30to120)(70to280)(120to640)20to60%1280to51202560to102405120to20480(360to1080)(840to2520)(1920to5760)
Heavy-dutyHeavy-dutyHeavy-dutyHeavy-dutyHeavy-dutyHeavy-duty
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