Designation:C158−02(Reapproved2012)StandardTestMethodsforStrengthofGlassbyFlexure(DeterminationofModulusofRupture)1ThisstandardisissuedunderthefixeddesignationC158;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thesetestmethodscoverthedeterminationofthemodulusofruptureinbendingofglassandglass-ceramics.1.2Thesetestmethodsareapplicabletoannealedandprestressedglassesandglass-ceramicsavailableinvariedforms.Alternativetestmethodsaredescribed;thetestmethodusedshallbedeterminedbythepurposeofthetestandgeometriccharacteristicsofspecimensrepresentativeofthematerial.1.2.1TestMethodAisatestformodulusofruptureofflatglass.1.2.2TestMethodBisacomparativetestformodulusofruptureofglassandglass-ceramics.1.3Thetestmethodsappearinthefollowingorder:SectionsTestMethodATestMethodB6to910to151.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.SpecifichazardstatementsaregiveninSection10andA1.5,A2.3.3,A2.4.3andA2.5.3.2.ReferencedDocuments2.1ASTMStandards:2C148TestMethodsforPolariscopicExaminationofGlassContainersE4PracticesforForceVerificationofTestingMachinesSI10-02IEEE/ASTMSI10AmericanNationalStandardforUseoftheInternationalSystemofUnits(SI):TheModernMetricSystem3.Terminology3.1Definitions:3.1.1glass-ceramics—solidmaterials,predominantlycrys-tallineinnature,formedbythecontrolledcrystallizationofglasses.3.1.2modulusofruptureinbending—thevalueofmaxi-mumtensileorcompressivestress(whichevercausesfailure)intheextremefiberofabeamloadedtofailureinbendingcomputedfromtheflexureformula:Sb5McI(1)where:M=maximumbendingmoment...
