Fatiguetestingisacriticalmethodforevaluatingthedurabilityandperformanceofmaterialsundercyclicloadingconditions.TheASTMSTP91manualprovidescomprehensiveguidelinesandstandardizedproceduresforconductingfatiguetests,ensuringconsistencyandreliabilityintestresults.Thismanualcoversvariousaspectsoffatiguetesting,includingspecimenpreparation,testsetup,datacollection,andanalysistechniques.Itservesasanessentialreferenceforengineers,researchers,andtechniciansworkinginmaterialsscienceandstructuralintegrityassessment.ByfollowingtheprotocolsoutlinedinASTMSTP91,professionalscanaccuratelypredictthefatiguelifeofmaterialsandmakeinformeddecisionsregardingmaterialselectionanddesignoptimizationforapplicationssubjectedtorepetitivestress.