Designation:D638−22StandardTestMethodforTensilePropertiesofPlastics1ThisstandardisissuedunderthefixeddesignationD638;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thistestmethodcoversthedeterminationofthetensilepropertiesofunreinforcedandreinforcedplasticsintheformofstandarddumbbell-shapedtestspecimenswhentestedunderdefinedconditionsofpretreatment,temperature,humidity,andtestingmachinespeed.1.2Thistestmethodisapplicablefortestingmaterialsofanythicknessupto14mm(0.55in.).However,fortestingspecimensintheformofthinsheeting,includingfilmlessthan1.0mm(0.04in.)inthickness,ASTMstandardD882isthepreferredtestmethod.Materialswithathicknessgreaterthan14mm(0.55in.)shallbereducedbymachining.1.3ThistestmethodincludestheoptionofdeterminingPoisson’sratioatroomtemperature.NOTE1—ThisstandardandISO527-1addressthesamesubjectmatter,butdifferintechnicalcontent.NOTE2—Thistestmethodisnotintendedtocoverprecisephysicalprocedures.Itisrecognizedthattheconstantrateofcrossheadmovementtypeoftestleavesmuchtobedesiredfromatheoreticalstandpoint,thatwidedifferencesmayexistbetweenrateofcrossheadmovementandrateofstrainbetweengagemarksonthespecimen,andthatthetestingspeedsspecifieddisguiseimportanteffectscharacteristicofmaterialsintheplasticstate.Further,itisrealizedthatvariationsinthethicknessesoftestspecimens,whicharepermittedbytheseprocedures,producevariationsinthesurface-volumeratiosofsuchspecimens,andthatthesevariationsmayinfluencethetestresults.Hence,wheredirectlycomparableresultsaredesired,allsamplesshouldbeofequalthickness.Specialadditionaltestsshouldbeusedwheremoreprecisephysicaldataareneeded.NOTE3—Thistestmethodmaybeusedfortestingphenolicmoldedresinorlaminatedmaterials.However,wherethesematerialsare...
