1、A Referencenumbe r ISO7685:1998 (E) INTERNATIONAL STANDARD ISO 7685 Firstedition 19980715 PlasticspipingsystemsGlassreinforced thermosettingplastics(GRP)pipes Determinationofinitialspecificring stiffness SystmesdecanalisationenmatiresplastiquesTubesenplastiques thermodurcissablesrenforcsdeverre(PRV)
2、Dterminationdelarigidit annulairespcifiqueinitialeISO7685:1998(E) ISO1998 Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmaybereproduced orutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingand microfilm,withoutpermissioninwritingfromthepublisher. Internatio
3、nalOrganizationforStandardization Casepostale56 CH1211Genve20 Switzerland Internet isoiso.ch PrintedinSwitzerland ii Foreword ISO(theInternationalOrganizationforStandardization)isaworldwide federationofnationalstandardsbodies(ISOmemberbodies).Theworkof preparingInternationalStandardsisnormallycarrie
4、doutthroughISO technicalcommittees.Eachmemberbodyinterestedinasubjectforwhich atechnicalcommitteehasbeenestablishedhastherighttoberepresented onthatcommittee.Internationalorganizations,governmentalandnon governmental,inliaisonwithISO,alsotakepartinthework.ISOcollab oratescloselywiththeInternationalE
5、lectrotechnicalCommission(IEC)on allmattersofelectrotechnicalstandardization. DraftInternationalStandardsadoptedbythetechnicalcommitteesare circulatedtothememberbodiesforvoting.PublicationasanInternational Standardrequiresapprovalbyatleast75%ofthememberbodiescasting avote. InternationalStandardISO76
6、85waspreparedbyTechnicalCommittee ISO/TC138, Plasticspipes,fittingsandvalvesforthetransportoffluids , SubcommitteeSC 6, Reinforcedplasticspipesandfittingsforall applications,incollaborationwithCEN/TC155, Plasticspipingsystems andductingsystems . ThisInternationalStandardisoneofaseriesofstandardsonte
7、stmethods forplasticspipingsystemsandductingsystems.INTERNATIONALSTANDARD ISO ISO7685:1998(E) 1 PlasticspipingsystemsGlassreinforcedthermosettingplastics (GRP)pipesDeterminationofinitialspecificringstiffness 1Scope ThisInternationalStandardspecifiesmethodsfordeterminingtheinitialspecificringstiffnes
8、sofglassreinforced thermosettingplastics(GRP)pipes.Twomethodsaregiven,andwithinthespecifieddeflectionlimitseachis equallyvalidandmaybeusedforanydiameter. 2Definitions ForthepurposesofthisInternationalStandard,thefollowingdefinitionsapply: 2.1 compressiveload (F) loadappliedtoapipetocauseadiametricde
9、flection Itisexpressedinnewtons. 2.2 verticaldeflection (y) verticalchangeindiameterofapipeinahorizontalpositioninresponsetoaverticalcompressiveload(see2.1) Itisexpressedinmetres. 2.3 relativeverticaldeflection (y/d m ) ratiooftheverticaldeflection y(see2.2)tothemeandiameterofthepipe d m (see2.4) 2.
10、4 meandiameter (d m ) diameterofthecirclecorrespondingwiththemiddleofthepipewallcrosssection Itisgiven,inmetres,byeitherofthefollowingequations: d m = d i + e d m = d e - e where d i istheaverageofthemeasuredinternaldiameters(see5.3.3),inmetres; d e istheaverageofthemeasuredexternaldiameters(see5.3.
11、3),inmetres; e istheaverageofthemeasuredwallthicknessesofthepipe(see5.3.2),inmetres.ISO7685:1998(E) ISO 2 2.5 specificringstiffness (S) aphysicalcharacteristicofthepipe,whichisameasureoftheresistancetoringdeflectionunderexternalload Thischaracteristicisdeterminedbytestingandisdefined,innewtonspersqu
12、aremetre,bytheequation S EI d = m 3 where E istheapparentmodulusofelasticityasdeterminedintheringstiffnesstest,innewtonspersquaremetre; I isthesecondmomentofareainthelongitudinaldirectionpermetrelength,expressedinmetrestothe fourthpowerpermetre,i.e. I e = 3 12 where e isthewallthicknessofthetestpiec
13、e,inmetres; d m isthemeandiameter(see2.4)ofthetestpiece,inmetres. 2.6 initialspecificringstiffness (S 0 ) initialvalueof SobtainedbytestinginaccordancewiththisInternationalStandard Itisexpressedinnewtonspersquaremetre. 3Principle Alengthofpipeisloadedthroughoutitslengthtocompressitdiametrically.Twow
14、aysaregivenfordoingthis, methodA(constantload)andmethodB(constantdeflection),eitherofwhichcanbeused: MethodA: Afterapplyingtheloadnecessarytogivearelativedeflectionof(3 0,5)%,theloadiskeptconstantfor aspecifiedperiodoftimeandthefinaldeflectionisdeterminedattheendofthisperiod. MethodB: Afterapplyingt
15、heloadnecessarytogivetheinitialrelativedeflectionspecifiedinthereferringstandard, thedeflectioniskeptconstantforaspecifiedperiodoftimeandattheendofthisperiodthefinalloadbeingapplied isdetermined. NOTEItisassumedthatthefollowingtestparametersaresetbythestandardmakingreferencetothisInternational Stand
16、ard: a) themethodtobeused(AorB); b) thelengthofthetestpieces(see5.1); c) thenumberoftestpieces(see5.2); d) ifapplicable,thedetailsofconditioningofthetestpieces(seeclause6); e) formethodB,therelativedeflectiontobeapplied(see7.3.3). 4Apparatus 4.1 Compressiveloadingmachine, comprisingasystemcapableofa
17、pplying,withoutshock,acompressive force(suitableformethodAorB)atacontrolledratethroughtwoparallelloadapplicationsurfacesconformingto 4.2sothatahorizontallyorientatedpipetestpiececonformingtoclause5canbecompressedvertically.The accuracyofloadingshallbe 1%ofthemaximumindicatedload.ISO ISO7685:1998(E)
18、3 4.2 Loadapplicationsurfaces 4.2.1Generalarrangement Thesurfacesshallbeprovidedbyapairofplates(see4.2.2),orapairofbeambars(see4.2.3),oracombination ofonesuchplateandonesuchbar,withtheirmajoraxesperpendiculartoandcentredonthedirectionof applicationoftheload F bythecompressiveloadingmachine,asshownin
19、figure1.Thesurfacesincontactwiththe testpieceshallbeflat,smooth,cleanandparallel. Platesandbeambarsshallhavealengthatleastequaltothatofthetestpiece(seeclause5)andathicknesssuch thatvisibledeformationdoesnotoccurduringthetest. 4.2.2Plates Theplate(s)shallhaveawidthofatleast100mm. 4.2.3Beambars Eachbe
20、ambarshallhaveroundededges,aflatface(seefigure1)withoutsharpedgesandawidthdependent uponthepipeasfollows: a) forpipeswithanominalsizenotgreaterthanDN300,thewidthshallbe20mm 2mm; b) forpipesof nominalsizesgreaterthanDN300,thewidthshallbe50mm 5mm. Thebeambarsshallbedesignedandsupportedsuchthatnoothers
21、urfaceofthebeambarstructurecomesinto contactwiththetestpieceduringthetest. 4.3 Dimensionmeasuringinstruments, capableofdetermining thenecessarydimensions(length,diameter,wallthickness)toanaccuracyofwithin 0,1mm; thedeflectionofthetestpieceintheverticaldirectiontoanaccuracyofwithin 1,0%ofthemaximumva
22、lue. Figure1SchematicdiagramofthetestarrangementISO7685:1998(E) ISO 4 5Testpieces 5.1Preparation Eachtestpieceshallbeacompleteringcutfromthepipetobetested.Thelengthofthetestpieceshallbeas specifiedinthereferringstandard,withpermissibledeviationsof 5%.Whereareferringstandarddoesnotexist ordoesnotspec
23、ifythelengthofthetestpiece,thesaidlengthshallbe300mm 15mm. Thecutendsshallbesmoothandperpendiculartotheaxisofthepipe. Straightlines,toserveasreferencelines,shallbedrawnontheinsideortheoutsidealongthelengthofthetest pieceat60intervalsarounditscircumference. 5.2Number Thenumberoftestpiecesshallbeasspe
24、cifiedinthereferringstandard.Whereareferringstandarddoesnotexist ordoesnotspecifythenumberoftestpiecesthesaidnumbershallbeoneperpipesize. 5.3Determinationofdimensions 5.3.1Length Measurethelengthofthetestpiecealongeachreferencelinetoanaccuracyof0,2mm. Calculatetheaveragelength L,inmetres,ofthetestpi
25、ecefromthesixmeasuredvalues. 5.3.2Wallthickness Measuretowithin 0,2mmthewallthicknessofthetestpieceateachendofeachreferenceline. Calculatetheaveragewallthickness e,inmetres,ofthe12measuredvalues. 5.3.3Meandiameter Measuretoanaccuracyofwithin 0,5mmeitherofthefollowing: a) theinternaldiameter d i ofth
26、etestpiecebetweeneachpairofdiametricallyopposedreferencelinesattheirmid length,e.g.bymeansofapairofcalipers; b) theexternaldiameter d e ofthetestpieceatthemidpointsofthereferencelines,e.g.bymeansof circumferentialwrapsteeltape. Calculatethemeandiameter d m ofthetestpieceusingthevaluesobtainedforwall
27、thicknessandeithertheinternal ortheexternaldiameter(see2.4). 6Conditioning Unlessotherwisespecifiedbythereferringstandard,storethetestpiecesforatleast0,5hatthetesttemperature (see7.1)priortotesting. Incasesofdispute,conditionthetestpiecesfor24hat23C 3Cbeforetesting,orsubjectthemtoamutually agreedcon
28、ditioningschedule. 7Procedure 7.1Testtemperature Conductthefollowingprocedureatthetemperaturespecifiedinthereferringstandard.ISO ISO7685:1998(E) 5 7.2Positioningofthetestpiece Placeatestpieceintheapparatuswithapairofdiametricallyopposedreferencelinesincontactwiththeplate(s) and/orbeambar(s). Ensuret
29、hatthecontactbetweenthetestpieceandeachplateorbeambarisasuniformaspossibleandthatthe plate(s)and/orbeambar(s)arenottiltedlaterally. 7.3Applicationofloadandmeasurementofdeflection 7.3.1General Carryoutatestinaccordancewith7.3.2or7.3.3ateachpairofreferencelines(see5.1).Allowthetestpieceto recoverbetwe
30、eneachtest.Incasesofdispute,allow15minbetweeneachtest. 7.3.2MethodA:Usingconstantload Seefigure2. Applythecompressiveloadatanapproximatelyconstantratesothatarelativedeflectionbetween2,5%and3,5% isreachedin60s 10s; Keepthisloadconstantfor2min,andattheendofthisperioddetermineandrecordtheloadandthedefl
31、ection. Figure2MethodA:Loadandcorrespondingdeflectionversustime 7.3.3MethodB:Usingconstantdeflection Seefigure3. Applythecompressiveloadatanaproximatelyconstantratesothatarelativedeflectionbetween2,5%and3,5% isreachedin60s 10s. Keepthisdeflectionconstantfor2min,andattheendofthisperioddetermineandrec
32、ordthedeflectionandthe load.ISO7685:1998(E) ISO 6 Figure3MethodB:Deflectionandcorrespondingloadversustime 8Calculation Calculatetheinitialspecificringstiffness S 0 foreachofthethreepositionsusingthefollowingequation: S fF Ly 0 = where f isthedeflectioncoefficient,givenbytheequation () fy d =+ - 1860
33、 2 500 10 5 / m ; L istheaveragelengthofthetestpiece,expressedinmetres; F istheappliedload,expressedinnewtons; y isthedeflection,expressedinmetres; d m isthemeandiameter,expressedinmetres. Calculatetheaverageofthethreevaluesandrecordthisvalueastheinitialspecificringstiffnessofthetestpiece. 9Testrepo
34、rt Thetestreportshallincludethefollowinginformation: a) areferencetothisInternationalStandardandthereferringstandard; b) alldetailsnecessaryforcompleteidentificationofthepipetested; c) thedimensionsofeachtestpiece; d) thenumberoftestpieces;ISO ISO7685:1998(E) 7 e) thepositionsinthepipefromwhichthete
35、stpieceswereobtained; f) theequipmentdetails,includingwhetherbeambarsand/orplateswereused; g) thetesttemperature; h) thetestmethodused,i.e.methodAorB; i) foreachtestpiece,theloadsandcorrespondingdeflectionsusedtocalculatetheinitialspecificringstiffness; j) theinitialspecificringstiffnessofeachtestpi
36、ece; k) anyfactorswhichmayhaveaffectedtheresults,suchasanyincidentswhichmayhaveoccurredorany operatingdetailsnotspecifiedinthisInternationalStandard; l) thedateofthetest.ISO7685:1998(E) ISO ICS23.040.20 Descriptors:piping,pipes(tubes),thermosettingresins,glassreinforcedplastics,plastictubes,tests,mechanicaltests,stiffn esstests, rulesofcalculation. Pricebasedon7pages
