Designation:D6874−22aStandardTestMethodsforNondestructiveEvaluationoftheStiffnessofWoodandWood-BasedMaterialsUsingTransverseVibrationorStressWavePropagation1ThisstandardisissuedunderthefixeddesignationD6874;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONNondestructivetestingmethodsareusedtodeterminethephysicalandmechanicalpropertiesofwoodandwood-basedmaterials.Thesetestmethodshelpensurestructuralperformanceofproductsmanufacturedfromavarietyofwoodspeciesandqualitylevelsofrawmaterials.Thesetestmethodsalsoassistinevaluatingtheinfluenceofenvironmentalconditionsonproductperformance.Dynamictestmethodsbasedonthetransversevibrationofasimplyorfreelysupportedbeam,orthepropagationofalongitudinalstresswavearemethodsusedtonondestructivelyevaluatewood-basedmaterials.Thesemethodsyieldresultscomparabletotraditionalstatictestmethods,permittingstandardizationofresults,interchangeandcorrelationofdata,andestablishmentofacumulativebodyofinformationonwoodspeciesandproductsoftheworld.1.Scope1.1Thesetestmethodscoverthenon-destructivedetermi-nationofthefollowingdynamicpropertiesofwoodandwood-basedmaterialsfrommeasuringthefundamentalfre-quencyofvibration:1.1.1Flexural(seeRefs(1-3))2stiffnessandapparentmodulusofelasticity(Etv)propertiesusingsimplyorfreelysupportedbeamtransversevibrationintheverticaldirection,and1.1.2Axialstiffnessandapparentlongitudinalmodulusofelasticity(Esw)usingstresswavepropagationtimeinthelongitudinaldirection.1.2Thetestmethodscanbeusedforabroadrangeofwood-basedmaterialsandproductsrangingfromlogs,timbers,lumber,andengineeredwoodproducts.1.2.1ThetwoflexuralmethodscanbeappliedtoflexuralproductssuchasglulambeamsandI-joists.1.2.2Thelongitudinalstresswavemethodsarelimitedtosolidwoodandhomogeneousgradeglulam(forexample,columnsbutnotproductswithdistinctsub...
