Author : Buhnnum Kyokong

Summary : A study was conducted to correlate dynamic modulus of elasticity (Ed) with static modulus of elasticity (Es) and modulus of rupture (R) of some Philippine woods. This involved a non-destructive method using sound waves as an exciting means and a photoelectric transducing mechanism for Ed measurement. Effects of moisture content and brashwood on the above parameters were also determined. The experiment was performed on specimens of 2 by 2 by 36 cm of normal apitong and tangile woods and also tangile brashwood. A total of 80 specimens for each species and, in addition, 40 specimens of tangile brashwood were used. Each specimen was first non-destructively tested under flexural forced-vibration technique and afterward subjected to a static bending test until failure occurred, at nominal moisture contents of 7%,13%,19%, and green condition. The data gathered were analyzed using simple linear regression and correlation concepts.