Estimating mechanical properties of clear wood from ten‐year‐old Melia azedarach trees using the stress wave method

The objective of this study was to examine the potential of stress wave velocity (SWV) as a rapid and non-destructive method to estimate the mechanical properties of Melia azedarach wood. The SWV, dynamic modulus of elasticity (MOE_d), modulus of elasticity (MOE), modulus of rupture (MOR, bending strength) and density were determined on ninety 20 ⋅ 20 ⋅ 320 mm clear wood specimens, obtained from stems of three ten-year-old M. azedarach trees, and tested at environmental equilibrium in 20°C, 60 % relative humidity (a moisture content of approximately 12 %). There was a statistically significant (0.1 % level) but weak correlation (R² = 0.23) between the SWV and MOE, but no statistically significant correlation was found between the SWV and MOR. Much better results for prediction of static properties of M. azedarach wood were obtained when SWV and wood density (WD) were used together through calculation of MOE_d in the air-dry condition (MOE: R² = 0.76, MOR: R² = 0.47), although in the case of MOR a model based on WD alone is slightly better (R² = 0.58), and WD is also almost as good as MOE_d for predicting MOE. It is concluded that SWV coupled with WD can be employed as a predicting parameter to evaluate the mechanical properties of M. azedarach wood during the manufacturing process, although WD alone is also effective. The SWV alone would not be useful due to MOE being almost directly proportional to WD at this moisture content.