Mechanical Properties of Unidirectional Oriented Strand Board with Flat Vertical Density Profile

Abstract

This study investigated the effect of the relative humidity (RH) and density of unidirectional strand board (USB) on parallel, perpendicular and through-the-thickness elastic modulus (E 1 , E 2 and E 3) and interlaminar shear modulus (G 13 and G 23). The relationships between these parameters and density were determined on unidirectional OSB panels with a flat density profile. The target densities were: 550, 700 and 850 kg/m 3. Two RH levels at a constant temperature of 20°C were used to determine relationships between USB mechanical properties and moisture content (MC). The analysis of variance (ANOVA) indicated that only density had a significant effect on the mechanical properties considered. Even though the effect of RH was not significant, a trend could be observed. Unidirectional strand board E 1 , E 2 , E 3 , G 13 and G 23 , increased with an increase in density and decreased with an increase in RH. Finally, a regression procedure was used to determine the linear or quadratic equation necessary to predict the mechanical properties of the USB panels as a function of density. A positive correlation was observed between the unidirectional USB properties considered and density. These data will support the modeling of the hygromechanical behaviour of the USB used as component in wood composite constructions.