Study of acoustic wave propagation through the cross section of green wood

An experimental approach was used to model stress wave propagation in green wood (Douglas fir). Based on the assumption that wood is an orthotropic material, the stress wave velocity through the cross section was calculated using plane strain motion equations. The experiments were carried out in two steps under axial restraint, while the wave propagation time was measured on discs and bars sliced from the discs. Mechanical and physical properties were determined in free vibration. The results showed a significant difference in propagation velocity between waves propagating throughout the whole disc volume and guided waves in bars. The acoustic anisotropy of green wood is discussed and the stress wave form simulation is presented. Good agreement between the simulation and experimental results was obtained.