Dynamic characteristics of 22 woods determined by the tranverse vibration method

Abstract

The timber industry requires information on the technological characteristics of the material so that they are incorporated in new products with added value. The aim of the research was to determine the density, dynamic modulus, modulus of rigidity and damping ratio of 22 species. For each species, 20 specimens were prepared and vibration tests were conducted under free-free condition support. Dynamic modulus, modulus of rigidity and the damping coefficient were assessed. For each variable the mean, standard deviation and coefficient of variation were calculated. Linear regressions were calculated for a significance level of 95 % and their coefficients of determination of the variables as a function of density. Each species showed different dynamic characteristics, which allowed to observe the wide range of values that can be found between different species. The density values are distributed among a minimum of 391 kg m^-3 (Gyrocarpus americanus) and a maximum of 1 096 kg m^-3 (Tabebuia chrysantha), which allowed to examine a wide interval of densities. The density was found to be a good predictor of dynamic modulus (R² = 0.86) and modulus of rigidity (R² = 0.79). No significant correlation of damping ratio with density was found (R² = 0.01).