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【英文标准名称】:StandardPracticeforDeterminingResistanceofSolarCollectorCoverstoHailbyImpactWithPropelledIceBalls
【原文标准名称】:用发射冰球法测定太阳能收集器覆盖材料对冰雹冲击抗力的标准实施规程
【标准号】:ASTME822-1992(2009)
【标准状态】:现行
【国别】:美国
【发布日期】:1992
【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】:E44.05
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:hail;iceballs;impact;impactresistance;solarcollector;Covermaterials--solarcollectors;Hail;Iceballs;Impactresistance;Propellediceballs;Solarcollectors
【摘要】:Inmanygeographicareasthereisconcernabouttheeffectoffallinghailuponsolarcollectorcovers.Thispracticemaybeusedtodeterminetheabilityofflat-platesolarcollectorcoverstowithstandtheimpactforcesofhailstones.Inthispractice,theabilityofasolarcollectorcoverplatetowithstandhailimpactisrelatedtoitstestedabilitytowithstandimpactfromiceballs.Theeffectsoftheimpactonthematerialarehighlyvariableanddependentuponthematerial.Thispracticedescribesastandardprocedureformountingthetestspecimen,conductingtheimpacttest,andreportingtheeffects.Theproceduresformountingcoverplatematerialsandcollectorsareprovidedtoensurethattheyaretestedinaconfigurationthatrelatestotheiruseinasolarcollector.Thecornerlocationsofthefourimpactsarechosentorepresentvulnerablesitesonthecoverplate.Impactsnearcornersupportsaremorecriticalthanimpactselsewhere.Onlyasingleimpactisspecifiedateachoftheimpactlocations.Fortestcontrolpurposes,multipleimpactsinasinglelocationarenotpermittedbecauseasubcriticalimpactmaystillcausedamagethatwouldaltertheresponsetosubsequentimpacts.Resultantvelocityisusedtosimulatethevelocitythatmaybereachedbyhailaccompaniedbywind.Theresultantvelocityusedinthispracticeisdeterminedbyvectoradditionofa20m/s(45mph)horizontalvelocitytotheverticalterminalvelocity.Iceballsareusedinthispracticetosimulatehailstonesbecausenaturalhailstonesarenotreadilyavailabletouse,andiceballscloselyapproximatehailstones.However,nodirectrelationshiphasbeenestablishedbetweentheeffectofimpactoficeballsandhailstones.Hailstonesarehighlyvariableinpropertiessuchasshape,density,andfrangibility.Thesepropertiesaffectfactorssuchasthekineticenergydeliveredtothecoverplate,theperiodduringwhichenergyisdelivered,andtheareaoverwhichtheenergyisdistributed.Iceballs,withadensity,frangibility,andterminalvelocityneartherangeofhailstones,arethenearesthailstoneapproximationknownatthistime.Perhapsthemajordifferencebetweeniceballsandhailstonesisthathailstonesaremuchmorevariablethaniceballs.However,iceballscanbeuniformlyandrepeatedlymanufacturedtoensureaprojectilewithknownproperties.Awiderangeofobservableeffectsmaybeproducedbyimpactingthevarioustypesofcoverplatematerials.Theeffectsmayvaryfromnoeffecttototaldestruction.Somechangesinthecovermaterialmaybevisiblewhenthereisnoapparentfunctionalimpairmentofthecoverplatematerial.Alleffectsofeachimpactmustbedescribedinthereportsothatanestimateoftheirsignificancecanbemade.Datageneratedusingthispracticemaybeused:(1)toevaluateimpactresistanceofasinglematerialorcollector,(2)tocomparetheimpactresistanceofseveralmaterialsorcollectors,(3)toprovideacommonbasisforselectionofcovermaterialsorcollectorsforuseinvariousgeographicareas,or(4)toevaluatechangesinimpactresistanceduetoenvironmentalfactorssuchasweather.Thispracticedoesnotstatethesize(s)oficeball(s)tobeusedinmakingtheimpact.Eitherthepersonrequestingthetestorthepersonperformingthetestmustdetermineiceballsizetobeusedinthetesting.Choiceoficeballsizemayrelatetotheintentofthetesting.Ifthetestingisbeingperformedtoevaluateimpactresistanceofasinglematerialorcollector,orseveralmaterialsorcollectors,itmaybedesirabletorepeatthetestusingseveralsizesoficeballs.Inthismannerthedifferenteffectsofvarioussizesoficeball......
【中国标准分类号】:F12
【国际标准分类号】:27_160
【页数】:5P.;A4
【正文语种】:英语