Dynamic Properties Of Wood Obtained By Frequency Resonance Technique And Dynamic Mechanical Analysis

Abstract

The study of the viscoelastic properties of wood involves the determination of dynamic parameters. Different methods can be used to determine these parameters, which bring the question of whether these parameters can be considered identical depending on the method used. This study compares the frequency resonance technique and dynamic mechanical analysis for determining the bending dynamic modulus of elasticity (MOED) and damping coefficient tan d of dry and green wood. Groups of specimens of European beech (Fagus sylvatica L.), small-leaved linden (Tilia cordata Mill.), European oak (Quercus robur L.), and Norway spruce (Picea abies L.) wood at three levels of MC were tested with both methods. The bending dynamic modulus of elasticity decreased with increasing MC until the FSP. There were no significant changes in dynamic modulus with increasing MC above FSP. A strong linear correlation between MOED obtained through both methods was found (r 5 0.92, r 2 5 0.84). For the damping coefficient tan d, the relationship was weaker (r 5 0.57, r 2 5 0.32), and each method showed a different influence of MC on the damping coefficient above the FSP, which leads to the conclusion that the damping coefficient is sensitive to the measurement method.