Document Type : Research Paper

Authors

• Mohammad ali Sadat nia ¹
• Ali akbar Enayati ²
• Loeic Brancheriau ³
• Kambiz Pourtahmasi ⁴
• Farhang Honarparvar ⁵

¹ Assistant Professor, Wood and Paper Sciences, Khatamoanbia University of Behbahan

² Professor, Wood and Paper Sciences, Tehran University

³ Assistant Professor, Mechanics Sciences, Montpellier University

⁴ Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran

⁵ Assistant Professor, Wood and Paper Sciences, Tehran University

Abstract

The acoustic behavior of reaction and normal woods, phase velocity, group velocity and attenuation coefficients in the main directions for two wood species (Populus deltoids & Picea abies), were measured and compared. The results did not show any significant difference between phase velocities of normal and tension wood at the same ring in poplar wood. But in compression wood from spruce, phase velocity in longitudinal direction was lower; while in transverse direction was higher compared to normal wood. Group velocity as an index of speed of wave energy in compression wood also was less than that in normal wood. In radial and tangential directions, there was no significant difference between group velocity of compression and normal woods of spruce. In poplar species, in all main directions, the measured group velocities, both for tension and normal woods were identical. The result also showed that the attenuation coefficients in reaction wood of two wood species (poplar and spruce) were less than those of normal wood in all directions. In compression and tension woods, a high correlation was observed between acoustic radiation and wood density.

Keywords

• tension wood
• compression wood
• acoustic behavior
• phase velocity
• attenuation coefficient