Determination of elastic properties of latewood and earlywood by digital image analysis technique

The proportion of latewood varies from species to species and from site to site. To understand the stiffness of wood structures, it is necessary to accurately determine the modulus of elasticity (MOE) of the wood. In this paper, a digital image correlation method was used to analyze the surface strain of wood specimens during tensile testing and calculate the Poisson's ratios of latewood and earlywood. Digital image analysis (DIA) and X-ray densitometry (XrD) techniques were employed to determine the latewood proportion. Good agreement was observed between the DIA and XrD results for the sapwood proportion. Based on the rule of mixtures, the effective MOE was calculated based on the MOEs of earlywood and latewood.