GW-16-ASTM-E83-06-Standard-Practice-for-Verificati

Designation:E83–06StandardPracticeforVerificationandClassificationofExtensometerSystems1ThisstandardisissuedunderthefixeddesignationE83;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.1.Scope1.1Thispracticecoversproceduresfortheverificationandclassificationofextensometersystems,butitisnotintendedtobeacompletepurchasespecification.Thepracticeisapplicableonlytoinstrumentsthatindicateorrecordvaluesthatareproportionaltochangesinlengthcorrespondingtoeithertensileorcompressivestrain.Extensometersystemsareclas-sifiedonthebasisofthemagnitudeoftheirerrors.1.2Becausestrainisadimensionlessquantity,thisdocu-mentcanbeusedforextensometersbasedoneitherSIorUScustomaryunitsofdisplacement.NOTE1—Bondedresistancestraingagesdirectlybondedtoaspecimencannotbecalibratedorverifiedwiththeapparatusdescribedinthispracticefortheverificationofextensometershavingdefinitegagepoints.(SeeproceduresasdescribedinTestMethodsE251.)1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2E6TerminologyRelatingtoMethodsofMechanicalTest-ingE21TestMethodsforElevatedTemperatureTensionTestsofMetallicMaterialsE251TestMethodsforPerformanceCharacteristicsofMetallicBondedResistanceStrainGages3.Terminology3.1Definitions:Inadditiontothetermslisted,seeTermi-nologyE6.3.1.1calibration—adeterminationofthecalibrationfactorforasystemusingestablishedprocedures.3.1.2calibrationfactor—thefactorbywhichthechangeinextensometerreadingmustbemultipliedtoobtaintheequiva-lentstrain.3.1.2.1Discussion—Foranyextensometer,thecalibrationfactorisequaltotheratioofchangeinlengthtotheproductofthegagelengthandthechangeintheextensometerreading.Fordirect-readingextensometersthecalibrationfactorisunity.3.1.3compressometer—aspecializedextensometerusedforsensingnegativeorcompressivestrain.3.1.4deflectometer—aspecializedextensometerusedforsensingofextensionormotion,usuallywithoutreferencetoaspecificgagelength.3.1.5error,inextensometersystems—thevalueobtainedbysubtractingthecorrectvalueofthestrainfromtheindicatedvaluegivenbytheextensometersystem.3.1.6extensometer,n—adeviceforsensingstrain.3.1.7extensometersystems—asystemforsensingandindi-catingstrain.3.1.7.1Discussion—Thesystemwillnormallyincludeanextensometer,conditioningelectronicsandauxiliarydevice(recorder,digitalreadout,computer,etc.).However,com-pletelyself-containedmechanicaldevicesarepermitted.Anextensometersystemmaybeoneofthreetypes.3.1.8Type1extensometersystem,n—anextensometersys-temwhichbothdefinesgagelengthandsensesextension,forexample,aclip-onstraingagetypewithconditioningelectron-ics.3.1.9Type2extensometersystem,n—anextensometerwhichsensesextensionandthegagelengthisdefinedbyspecimengeometryorspecimenfeaturessuchasridgesornotches.3.1.9.1Discussion—AType2extensometerisusedwheretheextensometergagelengthisdeterminedbyfeaturesonthespecimen,forexample,ridges,notches,oroverallheight(incaseofcompressiontestpiece).TheprecisionassociatedwithgagelengthsettingforaType2extensometershouldbespecifiedinrelevanttestmethodorproductstandard.ThepositionreadoutonatestingmachineisnotrecommendedforuseinaType2extensometersystem.1ThispracticeisunderthejurisdictionofASTMCommitteeE28onMechanicalTestingandisthedirectresponsibilityofSubcommitteeE28.01onCalibrationofMechanicalTestingMachinesandApparatus.CurrenteditionapprovedMay1,2006.PublishedJune2006.Originallyapprovedin1950.Lastpreviouseditionapprovedin2002asE83–02.2ForreferencedASTMstandards,visittheASTMwebsite,@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.—anextensometersystemwhichintrinsicallysensesstrain(ratiometricprinciple),forexample,videocamerasystem.3.1.11gagelength(L),n—theoriginallengthofthatportionofthespecimenoverwhichstrainorchangeoflengthisdetermined.3.1.11.1Discussion—Ifthedeviceisusedforsensingextensionormotion,andgagelengthispredeterminedbythespecimengeometryorspecifictestmethod,thenonlyresolu-tionandstrainerrorforaspecifiedgagelengthshoulddeterminetheclassofextensometersystem.3.1.12resolutionofthestrainindicator—thesmallestchangeinstrainthatcanbeestimatedorascertainedonthestrainindicatingapparatusofthetestingsystem,atanyappliedstrain.3.1.13resolutionofthedigitaltypestrainindicators(nu-mericdisplays,printouts,andsoforth)—theresolutionisthesmallestchangeinstrainthatcanbedisplayedonthestrainindicator(maybeasingledigitoracombinationofdigits)atanyappliedstrain