Designation:E1049−85(Reapproved2011)´1StandardPracticesforCycleCountinginFatigueAnalysis1ThisstandardisissuedunderthefixeddesignationE1049;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—Reference(12)waseditoriallycorrectedinOctober2011.1.Scope1.1Thesepracticesareacompilationofacceptableproce-duresforcycle-countingmethodsemployedinfatigueanalysis.Thisstandarddoesnotintendtorecommendaparticularmethod.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2E912DefinitionsofTermsRelatingtoFatigueLoading;ReplacedbyE1150(Withdrawn1988)33.Terminology3.1Definitions:3.1.1constantamplitudeloading—infatigueloading,aloadinginwhichallofthepeakloadsareequalandallofthevalleyloadsareequal.3.1.2cycle—infatigueloading,underconstantamplitudeloading,theloadvariationfromtheminimumtothemaximumandthentotheminimumload.NOTE1—Inspectrumloading,definitionofcyclevarieswiththecountingmethodused.3.1.3meancrossings—infatigueloading,thenumberoftimesthattheload-timehistorycrossesthemean-loadlevelwithapositiveslope(oranegativeslope,orboth,asspecified)duringagivenlengthofthehistory(seeFig.1).3.1.3.1Discussion—Forpurposesrelatedtocyclecounting,ameancrossingmaybedefinedasacrossingofthereferenceloadlevel.3.1.4meanload,Pm—infatigueloading,thealgebraicaverageofthemaximumandminimumloadsinconstantamplitudeloading,orofindividualcyclesinspectrumloading,Pm5~Pmax1Pmin!/2(1)ortheintegralaverageoftheinstantaneousloadvaluesorthealgebraicaverageofthepeakandvalleyloadsofaspec-trumloadinghistory.3.1.5peak—infatigueloading,thepointatwhichthefirstderivativeoftheload-timeh...
