1、BSISO9538:2025AerospaceseriesHydraulictubingjointsandfittingsPlanarflexuretestbsiNationalforewordThisBritishStandardistheUKimplementationofISO9538:2025.ItsupersedesBSISO9538:2017,whichiswithdrawn.TheUKparticipationinitspreparationwasentrustedtoTechnicalCommitteeACE69,Aerospacehydraulicsystems,fluids
2、andcomponents.Alistoforganizationsrepresentedonthiscommitteecanbeobtainedonrequesttoitscommitteemanager.ContractualandlegalconsiderationsThispublicationhasbeenpreparedingoodfaith,howevernorepresentation,warranty,assuranceorundertaking(expressorimplied)isorwillbemade,andnoresponsibilityorliabilityiso
3、rwillbeacceptedbyBSIinrelationtotheadequacy,accuracy,completenessorreasonablenessofthispublication.Allandanysuchresponsibilityandliabilityisexpresslydisclaimedtothefullextentpermittedbythelaw.Thispublicationisprovidedasis,andistobeusedattherecipientsownrisk.Therecipientisadvisedtoconsiderseekingprof
4、essionalguidancewithrespecttoitsuseofthispublication.Thispublicationisnotintendedtoconstituteacontract.Usersareresponsibleforitscorrectapplication.TheBritishStandardsInstitution2025PublishedbyBSIStandardsLimited2025ISBN9780539250701ICS49.080CompliancewithaBritishStandardcannotconferimmunityfromlegal
5、obligations.ThisBritishStandardwaspublishedundertheauthorityoftheStandardsPolicyandStrategyCommitteeon30June2025.Amendments/corrigendaissuedsincepublicationDateTextaffected、ISOInternationalStandardISO9538Thirdedition2025-06AerospaceseriesHydraulictubingjointsandfittingsPlanarflexuretestSerieaerospat
6、ialeJointsetraccordsdestuyauterieshydrauliques-EssaideflexionplaneReferencenumberISO9538:2025(en)COPYRIGHTPROTECTEDDOCUMENTISO2025Allrightsreserved.Unlessotherwisespecified,orrequiredinthecontextofitsimplementation,nopartofthispublicationmaybereproducedorutilizedotherwiseinanyformorbyanymeans,electr
7、onicormechanical,includingphotocopying,orpostingontheinternetoranintranet,withoutpriorwrittenpermission.PermissioncanberequestedfromeitherISOattheaddressbeloworISO,smemberbodyinthecountryoftherequester.ISOcopyrightofficeCP401Ch.deBlandonnet8CH-1214Vernier,GenevaPhone:+41227490111Email:copyrightiso.o
8、rgWebsite:www.iso.orgPublishedinSwitzerlandContentsPageForewordivIntroductionv1 Scope12 Normativereferences13 Termsanddefinitions14 Deviceforflexuretest15 Flexuretestspecimens36 Stressdetermination37 Procedure47.1 Instrumentationandstraingauges47.2 Frequency57.2.1 Testfrequency57.2.2 Naturalfrequenc
9、yofthespecimens57.2.3 Verificationofthenaturalfrequency57.3 Bendingstresscalibrationoftestspecimen57.4 Test58 Requirements5Bibliography7ForewordISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISOmemberbodies).TheworkofpreparingInternationalStandards
10、isnormallycarriedoutthroughISOtechnicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhastherighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmentabinliaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInt
11、ernationalElectrotechnicalCommission(IEC)onallmattersofelectrotechnicalstandardization.TheproceduresusedtodevelopthisdocumentandthoseintendedforitsfurthermaintenancearedescribedintheISO/IECDirectives,Part1.Inparticular,thedifferentapprovalcriterianeededforthedifferenttypesofISOdocumentshouldbenoted.
12、ThisdocumentwasdraftedinaccordancewiththeeditorialrulesoftheISO/IECDirectives,Part2(seewww.iso.org/directives).ISOdrawsattentiontothepossibilitythattheimplementationofthisdocumentmayinvolvetheuseof（八）patent(三).ISOtakesnopositionconcerningtheevidence,validityorapplicabilityofanyclaimedpatentrightsinr
13、espectthereof.Asofthedateofpublicationofthisdocument,ISOhadnotreceivednoticeof（八）patent(三)whichmayberequiredtoimplementthisdocument.However,implementersarecautionedthatthismaynotrepresentthelatestinformation,whichmaybeobtainedfromthepatentdatabaseavailableatwww.iso.org/patents.ISOshallnotbeheldrespo
14、nsibleforidentifyinganyorallsuchpatentrights.Anytradenameusedinthisdocumentisinformationgivenfortheconvenienceofusersanddoesnotconstituteanendorsement.Foranexplanationofthevoluntarynatureofstandards,themeaningofISOspecifictermsandexpressionsrelatedtoconformityassessment,aswellasinformationaboutISOsa
15、dherencetotheWorldTradeOrganization(WTo)principlesintheTechnicalBarrierstoTrade(TBT),seeWWW.isoQrgisoforeword.htmLThisdocumentwaspreparedbyTechnicalCommitteeISO/TC20,Aircraftandspacevehicles,SubcommitteeSC10,Aerospacefluidsystemsandcomponents.Thisthirdeditioncancelsandreplacesthesecondedition(ISO953
16、8:2017),whichhasbeentechnicallyrevised.Themainchangesareasfollows:一ClaUSe4andClaUSe7wereupdated.Anyfeedbackorquestionsonthisdocumentshouldbedirectedtotheusersnationalstandardsbody.AcompletelistingofthesebodiescanbefoundatWWW.isoQrgmembnrs.htmLIntroductionThetestproceduredescribedcanbeappliedasanalte
17、rnativetotherotarytestprocedurespecifiedinISO7257.ThequalificationtestproceduresfortubefittingsarespecifiedinISO7169.Othertestmethodscanbeusedaslongastheydevelopthesameresultsastheprocedurespecifiedinthisdocument.BSISO9538:2025AerospaceseriesHydraulictubingjointsandfittings一Planarflexuretest1 ScopeT
18、hisdocumentspecifiesaplanarflexuretestprocedureforreconnectableandpermanenthydraulictubejointsandfittings.Thisprocedureisintendedforconductingflexuretestsonfittingswithhigh-strengthhydraulictubesmadeofcorrosion-resistingSteeLtitaniumandaluminiumforuseoncommercialandmilitaryaircraft.2 Normativerefere
19、ncesTherearenonormativereferencesinthisdocument.3 TermsanddefinitionsNotermsanddefinitionsarelistedinthisdocument.ISOandIECmaintainterminologydatabasesforuseinstandardizationatthefollowingaddresses:一ISOOnlinebrowsingplatform:availableathttps:WWW.iso.org/obp一IECElectropedia:availableathttps:WWW.elect
20、ropedia.org/4 DeviceforflexuretestThetestdeviceshouldbesimilartothatshowninFigUreLItshallconsistofavibrator,amanifoldtoreceivethetestspecimens,andahydraulicsupplyunitcapableofconstantlymaintainingthestaticoperatingpressureduringtesting,includingmonitorsinducingtheshutdownofthesystemintheeventofpress
21、uredrop.Thenumberoftestspecimensshallbedefinedbythespecificationusedtoqualifythefitting.ISO2025-AllrightsreservedKey1pressuresupply2pressuregauge3testspecimenFigure 1 Set-upoftestdriveThetestspecimensareattachedtooppositeendsofthemanifold,whichisrigidlymountedonthevibrator.Themanifoldshallbesodesign
22、edandassembledthatanyrotationshallbeavoidedduringtesting.Ahoseassemblyestablishestheconnectionwiththehydraulicsupplyunit.Thevibratorshallallowforvibrationfrequenciesupto300Hz.Key1straingaugesforstresscycleassessmentinthetubeduringvibration2accelerometer3pressureportmanifold4vibratorFigure 2 Detailso
23、fset-up5 FlexuretestspecimensThetestspecimensshallconsistofthetubefittingtobetested(e.g.straightunion),thetesttubeandthefittingtosealthetube.6 StressdeterminationThemaximumpermissibleflexurefatiguestressofthetesttubingisdeterminedforthecombinedstresslevel.Thecombinedstress,fiscomposedofthetensilestr
24、ess,肾SUItingfromtheinternalpressureandthewallthicknessofthetube,andthebendingstress,b.Straingaugesshallbeusedtodemonstratethebendingstress;andthedeflectioncanbecheckedduringtestingbymeansofanglegauges.AtypicalstresscycleisillustratedinFigUre3.Thebendingstress,bisdeterminedbythemaximumpermissibleflex
25、urefatiguestressofthetesttubeandshallbespecifiedforeachapplication.1maximumstress2minimumstresspmeanaxialstressproducedbyinternalpressurebstresscausedbybendingfcombinedstress,p+bFigure 3 Typicaltestcycle7Procedure3.1 InstrumentationandstraingaugesAstraingaugeshallbemountedoneachtestspecimen.Theyshal
26、lbeofunidirectionaltype,mountedtothetubeandorientedasshowninFigUre4.Theirlocationshouldbeasfollows:a) fortubesizestoDN16:approximately4mmfromtheattachment-pointtubetofitting;b) fortubesizestoDN20andabove:approximately8mmfromtheattachment-pointtubetofitting.Key1234Fstraingaugevibratorsee7.1lengthgivi
27、ngnaturalfrequencyofbetween110Hzand120HzstaticloadFigure 4 Locationofgauges7.2 Frequency7.2.1 TestfrequencyThetestshouldbeperformedatapproximately100Hz.7.2.2 NaturalfrequencyofthespecimensTominimizethepowerinputofthevibratorused,thenaturalfrequencyofthespecimensshouldbewithinthefrequencyrange110Hzto
28、120Hz.Thetestfrequencyshallbeapproximately10%to20%belowthenaturalfrequencyofthespecimenstopreventtheirresonancerangefrombeingreached.7.2.3 VerificationofthenaturalfrequencyThespecimenlengthshallbedeterminedinorderthatthetheoreticalfirstbendingnaturalfrequencyshallbeintherangementionedin7.2.2.Theveri
29、ficationofthetheoreticalnaturalfrequencyshallbeperformedaccordingtothefollowingprocedure.a) Screwthefullyassembledtube,fittedwithstraingauges,intotheheader.b) Fillthespecimenwiththetestfluid.c) Drainthespecimeninordertoavoidanypresenceofair.d) Connectthestraingaugestothemeasuringdeviceandadjustthega
30、intosetthezero.e) Implementanaccelerometerontheheaderandconnectittothemeasuringdevice.f) Applythespecifiednominalpressure.g) Performasinefrequencyup-sweepscanfrom5Hzto200Hzanddown-sweepscanfrom200Hzto5Hzwithalogarithmicsweeprateofapproximately1octaveperminuteandanaccelerationpeakvalueof1g.h) Determi
31、netheresonantfrequencyofthespecimensbypost-treatmentofthestraingaugesresponse,applythenominalpressureandvibratethetube.7.3 BendingstresscalibrationoftestspecimenSubmitthepreparedtubetoastaticload(F)correspondingtothespecifiedbendingstress(seeClause4)inordertoproducetherequiredmoment.Afterthetubebend
32、ingsettingiscomplete,introducethespecifiedpressureandreadthestresstransmittedbythestraingaugeonanoscilloscope.7.4 TestStartthevibratorandsetthefrequencyinarangeof80%to90%oftheresonantfrequencymeasuredin7.2.3;increasethevibrationamplitudeofthevibratoruntiltheoscillographshowsthepreviouslydeterminedst
33、ressvalue.Anglegaugemountedontheextremityofeachspecimencanbeusedtoallowbettervisualisationofthedeflection.Tocontrolthedeflectionofthetestspecimen,asuitablestroboscopewithvariableflashfrequencyshallbeused.8RequirementsTheflexuretestspecimensshallwithstandIO7cycles.Leakagesandfailuresarenotacceptable.
34、Bibliography1 ISO7169,AerospaceSeparabletubefittingsforfluidsystems,for24degreecones,forpressuresupto3000psior21000kPaProcurementspecification,inch/methc2 ISO7257,AircraftHydraulictubingjointsandfittingsRotaryflexuretestNOCOPYINGWITHOUTBSIPERMISSIONEXCEPTASPERMITTEDBYCOPYRIGHTLAWBritishStandardsInst
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