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【英文标准名称】:StandardTestMethodsforFlexuralPropertiesofUnreinforcedandReinforcedPlasticsandElectricalInsulatingMaterials
【原文标准名称】:非增强和增强塑料和电绝缘材料的挠性特性的标准试验方法
【标准号】:ASTMD790-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D20.10
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:flexuralproperties;plastics;stiffness;strength;Electricalinsulatingplastics;Flexuraltesting--electricalinsulatingmaterials;Flexuraltesting--plastics;Reinforcedplastics;Stiffness--plastics;Unreinforcedplastics
【摘要】:Flexuralpropertiesasdeterminedbythesetestmethodsareespeciallyusefulforqualitycontrolandspecificationpurposes.Materialsthatdonotfailbythemaximumstrainallowedunderthesetestmethods(3-pointbend)maybemoresuitedtoa4-pointbendtest.Thebasicdifferencebetweenthetwotestmethodsisinthelocationofthemaximumbendingmomentandmaximumaxialfiberstresses.Themaximumaxialfiberstressesoccuronalineundertheloadingnosein3-pointbendingandovertheareabetweentheloadingnosesin4-pointbending.Flexuralpropertiesmayvarywithspecimendepth,temperature,atmosphericconditions,andthedifferenceinrateofstrainingasspecifiedinProceduresAandB(seealsoNote7).Beforeproceedingwiththesetestmethods,referenceshouldbemadetotheASTMspecificationofthematerialbeingtested.Anytestspecimenpreparation,conditioning,dimensions,ortestingparameters,orcombinationthereof,coveredintheASTMmaterialspecificationshalltakeprecedenceoverthosementionedinthesetestmethods.Table1inClassificationSystemD4000liststheASTMmaterialspecificationsthatcurrentlyexistforplastics.1.1Thesetestmethodscoverthedeterminationofflexuralpropertiesofunreinforcedandreinforcedplastics,includinghigh-moduluscompositesandelectricalinsulatingmaterialsintheformofrectangularbarsmoldeddirectlyorcutfromsheets,plates,ormoldedshapes.Thesetestmethodsaregenerallyapplicabletobothrigidandsemirigidmaterials.However,flexuralstrengthcannotbedeterminedforthosematerialsthatdonotbreakorthatdonotfailintheoutersurfaceofthetestspecimenwithinthe5.0%strainlimitofthesetestmethods.Thesetestmethodsutilizeathree-pointloadingsystemappliedtoasimplysupportedbeam.Afour-pointloadingsystemmethodcanbefoundinTestMethodD6272.1.1.1ProcedureA,designedprincipallyformaterialsthatbreakatcomparativelysmalldeflections.1.1.2ProcedureB,designedparticularlyforthosematerialsthatundergolargedeflectionsduringtesting.1.1.3ProcedureAshallbeusedformeasurementofflexuralproperties,particularlyflexuralmodulus,unlessthematerialspecificationstatesotherwise.ProcedureBmaybeusedformeasurementofflexuralstrengthonly.TangentmodulusdataobtainedbyProcedureAtendstoexhibitlowerstandarddeviationsthancomparabledataobtainedbymeansofProcedureB.1.2Comparativetestsmayberuninaccordancewitheitherprocedure,providedthattheprocedureisfoundsatisfactoryforthematerialbeingtested.1.3ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesprovidedinparenthesesareforinformationonly.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Note18212;ThesetestmethodsarenottechnicallyequivalenttoISO178.
【中国标准分类号】:K15
【国际标准分类号】:29_035_20
【页数】:11P.;A4
【正文语种】:英语