Experimental Analysis of Acoustic Anisotropy of Green Wood by using Guided Waves

Abstract

In this investigation we present an experimental analysis of the acoustic anisotropy of wood, in particular the dependence between the propagation velocities of stress waves and the natural anisotropy axis in the cross section. Wave velocities are measured on Douglas discs samples and on bars obtained from slicing discs. The experimentations are carried under cantilever conditions. Elasticity modulus and densities are determined in free vibrations. The results show a significant difference in propagation velocity between waves propagating in whole volume and waves guided on bars. Under cantilevering conditions the modulus of elasticity increases with the applied stress. The acoustic anisotropy of wood is discussed and the simulation of stress wave form was presented.