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【英文标准名称】:StandardPracticeforDeterminingSandwichBeamFlexuralandShearStiffness
【原文标准名称】:夹层梁抗弯和剪切刚度测定标准规范
【标准号】:ASTMD7250/D7250M-2006
【标准状态】:现行
【国别】:美国
【发布日期】:2006
【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】:D30.09
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:coreshearmodulus;flexuralstiffness;sandwichconstruction;sandwichdeflection;shearrigidity;shearstiffness
【摘要】:Flexuretestsonflatsandwichconstructionsmaybeconductedtodeterminethesandwichflexuralstiffness,thecoreshearstrengthandshearmodulus,orthefacingscompressiveandtensilestrengths.Teststoevaluatecoreshearstrengthmayalsobeusedtoevaluatecore-to-facingbonds.Thispracticeprovidesastandardmethodofdeterminingsandwichflexuralandshearstiffnessandcoreshearmodulususingcalculationsinvolvingmeasureddeflectionsofsandwichflexurespecimens.Testscanbeconductedonshortspecimensandonlongspecimens(orononespecimenloadedintwoways),andtheflexuralstiffness,shearrigidityandcoreshearmoduluscanbedeterminedbysimultaneoussolutionofthecompletedeflectionequationsforeachspanoreachloading.Ifthefacingmodulusvaluesareknown,ashortspanbeamcanbetestedandthecalculatedbendingdeflectionsubtractedfromthebeamrsquo;totaldeflection.Thisgivesthesheardeflectionfromwhichthetransverseshearmoduluscanbedetermined.Note18212;CoreshearstrengthandshearmodulusarebestdeterminedinaccordancewithTestMethodC273providedbarecorematerialisavailable.Note28212;Forcoreswithhighshearmodulus,thesheardeflectionwillbequitesmallandordinaryerrorsindeflectionmeasurementswillcauseconsiderablevariationsinthecalculatedshearmodulus.Note38212;Toinsurethatsimplesandwichbeamtheoryisvalid,agoodruleofthumbforafour-pointbendingtestisthespanlengthdividedbythesandwichthicknessshouldbegreaterthan20(L1/d>20)withtheratiooffacingthicknesstocorethicknesslessthan0.1(t/cx003C;0.1).1.1Thispracticecoversdeterminationoftheflexuralandtransverseshearstiffnesspropertiesofflatsandwichconstructionssubjectedtoflexureinsuchamannerthattheappliedmomentsproducecurvatureofthesandwichfacingplanes.Permissiblecorematerialformsincludethosewithcontinuousbondingsurfaces(suchasbalsawoodandfoams)aswellasthosewithdiscontinuousbondingsurfaces(suchashoneycomb).Thecalculationmethodsinthispracticearelimitedtosandwichbeamsexhibitinglinearforce-deflectionresponse.ThispracticeusestestresultsobtainedfromTestMethodsC393/C393Mand/orD7249/D7249M.1.2ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Withinthetexttheinch-poundunitsareshowninbrackets.Thevaluesstatedineachsystemarenotexactequivalents;therefore,eachsystemmustbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnonconformancewiththestandard.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:B70
【国际标准分类号】:79_060_01
【页数】:8P.;A4
【正文语种】:英语