Dynamic modulus assessment by stress waves in Acer saccharum Marshall and Thuja plicata L. wood

Abstract

The research goal was to assess the stress wave speed in the longitudinal

and radial directions of Acer saccharum Marshall and Thuja plicata

L. wood, and weighting this parameter with the wood density, to

determine the dynamic modulus of elasticity. For each species, 32 addoc

wood specimens were prepared with an average moisture content

of 11 % in which stress waves tests were realized. The experimental

design consisted in normality and difference of means tests. The response

variables were the wood density, and for the longitudinal and

tangential directions, the speed of the stress waves and the dynamic

modulus. The wood species was considered the variation factor. The

stress waves method allowed the dynamic characterization of A. saccharum

and T. plicata wood. Significant statistical difference was found

between the response variables. The density of A. saccharum wood is

greater than the corresponding to T. plicata wood. In the longitudinal

direction, the stress wave speed and dynamic modulus of A. saccharum

wood are lower than the T. plicata ones. In the tangential direction, the

stress wave speed of A. saccharum is bigger than the T. plicata wood.

In contrast, the dynamic modulus is smaller. When compared to the

tangential direction, the stress wave speed and dynamic modulus are

bigger in the longitudinal direction for both species.