【英文标准名称】:TestMethodforObtainingHydrostaticDesignBasisforThermoplasticPipeMaterials
【原文标准名称】:获得热塑性管道材料静水压设计基数的试验方法
【标准号】:ANSI/ASTMD2837-2004
【标准状态】:作废
【国别】:美国
【发布日期】:2004-06-01
【实施或试行日期】:2004-06-01
【发布单位】:美国国家标准学会(ANSI)
【起草单位】:ASTM
【标准类型】:()
【标准水平】:()
【中文主题词】:试验;塑料;热塑性聚合物;管
【英文主题词】:Basis;Design;Hydrostatic;Pipelines;Pipes;Plasticpipes;Plastics;Testing;Thermoplastic;Thermoplasticpolymers
【摘要】:Thistestmethoddescribestwoessentiallyequivalentprocedures:oneforobtainingalong-termhydrostaticstrengthcategorybasedonstress,referredtohereinasthehydrostaticdesignbasis(HDB);andtheotherforobtainingalong-termhydrostaticstrengthcategorybasedonpressure,referredtohereinasthepressuredesignbasis(PDB).TheHDBisbasedonthematerial'slong-termhydrostaticstrength(LTHS),andthePDBisbasedontheproduct'slong-termhydrostaticpressure-strength(LTHS).TheHDBisamaterialpropertyandisobtainedbyevaluatingstressrupturedataderivedfromtestingpipemadefromthesubjectmaterial.ThePDBisaproductspecificpropertythatreflectsnotonlythepropertiesofthematerial(s)fromwhichtheproductismade,butalsotheinfluenceonproductstrengthbyproductdesign,geometry,anddimensionsandbythespecificmethodofmanufacture.ThePDBisobtainedbyevaluatingpressurerupturedata.TheLTHSisdeterminedbyanalyzingstressversustime-to-rupture(thatis,stress-rupture)testdatathatcoveratestingperiodofnotlessthan10000handthatarederivedfromsustainedpressuretestingofpipemadefromthesubjectmaterial.Thedataareanalyzedbylinearregressiontoyieldabest-fitlog-stressversuslogtime-to-failstraight-lineequation.Usingthisequation,thematerial'smeanstrengthatthe100000-hintercept(LTHS)isdeterminedbyextrapolation.TheresultantvalueoftheLTHSdeterminestheHDBstrengthcategorytowhichthematerialisassigned.TheLTHSissimilarlydeterminedexceptthatthedeterminationisbasedonpressureversustimedatathatarederivedfromaparticularproduct.ThecategorizedvalueoftheLTHSisthePDB.AnHDB/PDBisoneofaseriesofpreferredlong-termstrengthvalues.Thistestmethodisapplicabletoallknowntypesofthermoplasticpipematerialsandthermoplasticpipingproducts.Itisalsoapplicableforanypracticaltemperatureandmediumthatyieldsstress-rupturedatathatexhibitanessentiallystraight-linerelationshipwhenplottedonlogstress(pound-forcepersquareinch)orlogpressure(pound-forcepersquarein.gage)versuslogtime-to-fail(hours)coordinates,andforwhichthisstraight-linerelationshipisexpectedtocontinueuninterruptedthroughatleast100000h.Unlesstheexperimentallyobtaineddataapproximateastraightline,whencalculatedusinglog-logcoordinates,itisnotpossibletoassignanHDB/PDBtothematerial.Datathatexhibithighscatterora"knee"(adownwardshift,resultinginasubsequentlysteeperstress-ruptureslopethanindicatedbytheearlierdata)butwhichmeettherequirementsofthistestmethodtendtogivealowerforecastofLTHS/LTHS.Inthecaseofdatathatexhibitexcessivescatterorapronounced"knee,"thelowerconfidencelimitrequirementsofthistestmethodarenotmetandthedataareclassifiedasunsuitableforanalysis.Afundamentalpremiseofthistestmethodisthatwhentheexperimentaldatadefineastraight-linerelationshipinaccordancewiththistestmethod'srequirements,thisstraightlinemaybeassumedtocontinuebeyondtheexperimentalperiod,throughatleast100000h(thetimeinterceptatwhichthematerial'sLTHS/LTHSisdetermined).Inthecaseofpolyethylenepipingmaterials,thistestmethodincludesasupplementalrequirementforthe"validating"ofthisassumption.Nosuchvalidationrequirementsareincludedforothermaterials(seeNote1).Therefore,inalltheseothercases,itisuptotheuserofthistestmethodtodeterminebasedonoutsideinformationwhetherthistestmethodissatisfactoryfortheforecastingofamaterial'sLTHS/LTHSforeachparticularcombinationofinternal/externalenvironmentsandtemperature.
【中国标准分类号】:P94
【国际标准分类号】:23_040_20
【页数】:
【正文语种】:英语