Determination of Young's modulus for spruce, fir and isotropic materials by the resonance flexure method with comparisons to static flexure and other dynamic methods

Abstract

Dynamic methods provide rapid and accurate means to determine Young's modulus, i.e. the modulus of elasticity, of wood. For dry, clear specimens of epicea common (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-point static flexure tests. For a wide range of specimen size the resonance flexure method provides a simpler, more rapidly performed alternative to the classical static flexure method, giving Young's modulus values which are for the spruce and fir specimens of this study, nearly identical to those caalculated from the static flexure tests. Results are also presented which show that a resonance longitudinal method yields higher values of Young's modulus and an ultrasonic method yields still higher values. We provide also a comparison of the four test methods applied to isotropic materials.