Abstract

Wood is important in several fields including sculpture and instrument making. In the last two fields, Terminalia superba, Cleistopholis patens, and Holarrhena floribunda are three of Benin’s most used wood species. In this work, we have, on prismatic samples (500 mm × 20 mm × 20 mm) of the wood of these species, used the acoustic method Beam Identification by Non-destructive Grading (BING) of CIRAD-Forêt to determine the density ρ, Young's modulus E, shear modulus G and internal friction tan ? that allowed the evaluation of the specific stiffness modulus E/ρ and the other acoustic parameters. These tests showed that T. superba, C. patens and H. floribunda wood species have specific moduli of elasticity of 18 ± 3, 17 ± 2 and 15 ± 1 GPa, respectively; internal friction of the order of 10^-2  and sound velocities of the order of 4000 m s^-1. All these three species have an average acoustic strength above 1.40 MPa s m^-1 with acoustic radiation above 7 m⁴ kg^-1 s^-1 for a high ACE above 1000 m⁴ kg^-1 s^-1 for T. superba and C. patens and low around 674 m⁴ kg^-1 s^-1 for H. floribunda. All these species have a medium stability in service and a low propensity to deformation due to their shrinkage anisotropy. In view of these results, the wood of these species can be used in both structural and acoustic works specifically in sound insulation, art sculpture and instrument making.

Key words: Specific modulus, internal friction, sound velocity, acoustic radiation, acoustic impedance, acoustic conversion efficiency, insulation, musical instrument.