DETERMINATION OF YOUNGS MODULUS FOR SPRUCE, FIR AND ISOTROPIC MATERIALS BY THE RESONANCE FLEXURE METHOD WITH COMPARISONS TO STATIC FLEXURE AND OTHER DYNAMIC METHODS

Dynamic methods provide rapid and accurate means to determine Young's modulus, i.e. the modulus of elasticity, of wood. For dry, clear speci mens of epicea commun (Norway spruce, picea excelsa) and sapin pictine (silver fir, abies amabilis) we present a comparison of results from tests by a resonance flexure method with results obtained from four-po int static flexure tests. For a wide range of specimen size the resona nce flexure method provides a simpler, more rapidly performed alternat ive to the classical static flexure method, giving Young's modulus val ues which are for the spruce and fir specimens of this study, nearly i dentical to those calculated from the static flexure tests. Results ar e also presented which show that a resonance longitudinal method yield s higher values of Young's modulus and an ultrasonic method yields sti ll higher values. We provide also a comparison of the four test method s applied to isotropic materials.