Determination of Poisson’s ratios in relation to fiber angle of a tropical wood species

This study examines the numerical variation of Poisson’s ratio with fiber direction for the tropical wood species Goupia glabra, whose products have significant applications in civil construction. Knowledge of mechanical properties is necessary when applying numerical methods to wood structure design, especially large-span structures, such as bridge structures with orthotropic plates. A theoretical elastic rectilinear orthotropic model with three principal directions of elasticity: longitudinal (L), radial (R), and tangential (T) has been adopted in development of this study. To determine Poisson’s ratios and their values, compression tests are performed on small prismatic test specimens. The numerical variation in two principal planes of elasticity, LR and LT, is verified. The results from both experimental tests and an orthotropic model approach are compared. The average differences between the theoretical and experimental values for the Poisson’s ratios are in the range of 2–15%, except for the angle 75° for the plane LT and for the angle 90° for the both planes. Considering wood’s heterogeneity and anisotropic behavior, the results of Poisson’s ratios indicate a satisfactory fit. In general, such results provide numerical information on this elastic parameter of a tropical wood species, extensively used in construction.