Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests

Abstract

Abstract Young's modulus and shear modulus were simultaneously obtained in a three-point bending test based on Timoshenko's bending theory. Deflection curves of a bent beam were measured by image analysis, and the mechanical properties of the wood were calculated by polynomial regression analysis after excluding the singular region. When beam specimens of spruce (Picea sp.) and mizunara (Quercus crispula) wood were tested, static Young's modulus (E s) and static shear modulus (G s) values could be obtained from the deflection curve using finite element analysis. By comparing the dynamic properties (E d and G d) obtained by a flexural vibration test, it was estimated that E s was greater than E d, while G s was less than G d. However, we suppose that the G s values calculated from the deflection curve are more plausible than those obtained from a conventional bending test.