Measuring elastic constants of Hevea brasiliensis using compression and Iosipescu shear test

The increasing demand and widespread utility of wood composite products necessitate the knowledge of the orthotropic engineering and strength properties of the raw wood used for its safe design and effective performance. This research study aimed at finding the orthotropic elastic parameters of a sustainable timber in India, namely rubber wood (Hevea brasiliensis) with respect to the material axes longitudinal (L), radial (R) and tangential (T), which is a potential raw material for laminated products as verified. This study evaluated the three Young's moduli, the three shear moduli and the six Poisson's ratios of the wood species, unavailable in literature. Compression test in rectangular prism was used for the determination of the Young's moduli and Poisson's ratios. Shear characterization in the three material planes was done using the Iosipescu test. The highest value of normal stiffness of the material in compression was obtained in the longitudinal direction followed by radial stiffness and tangential stiffness. The shear stiffness was largest in the LR plane followed by LT and RT planes. RT plane exhibited the highest Poisson's ratio and TL plane the lowest. Significant difference was noted in the shear strength of LR planes between block shear test and Iosipescu test but not with the LT planes.