Comparison of Viscous Elastic Properties in Wood of Leaf and Coniferous Tree

Abstract

The mechanical properties of wood polymeric system are defined in terms of viscous elastic materials. These
properties have an impact on relaxation processes for both wooden specimens and wooden articles. In this paper
the method of estimation of dynamic modulus of elasticity and coefficient of damping based on resonance
vibration is presented. All sorts of trees by wood structure may be classified into leaf and coniferous tree. The
structure of wood determines their different properties. Therefore in many cases leafy and coniferous trees are used
in different purposes. Spruce (coniferous tree) and oak (leaf tree) wood specimens have been used in the
investigation and the viscous elastic properties of these wood types were compared together. The specimens were
sawn from three places of central and side boards and they were relatively called “butt-end”, “center” and “topend”.
It was found that modulus of elasticity in central and side boards of oak and spruce varied conversely – in
center of oak boards the modulus of elasticity is highest, in center of spruce boards the modulus of elasticity is
lowest. The coefficient of damping in both central and side boards of oak and side boards of spruce varied
analogically.