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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

Nondestructive Testing for Strength and Elasticity of Some Philippines Woods by Forced Vibration.

(Thailand), Master of Science (University of the Philippines Los Baños)

Thesis Abstract:

 

The study was conducted to  correlate dynamic modulus of elasticity (Ed) with static modulus of Elasticity (Es) and modulus of rapture (R) of some Philippines woods. The testing involved a nondestructive method using sound waves as the existing force and photoelectric transducing mechanism for Ed measurement, Effects of moisture content and brashwood on the above parameters were also determined.

The experiment was performed on 80 specimens each of normal apitong and tangile woods and 40 specimens of tangile brashwood. Each specimen was first nondestructively tested under flexural forced-vibration technique and then subjected to a static bending test until failure occurred, at nominal moisture contents of 7, 13 and 19% and under green condition Simple linear regression and correlation (r=0.92) between Ed and Es for both wood species R for the ywo species could also be equally predicted by Ed or Es with reasonable accuracy (r=0.84);

As moisture content increased the more Ed and Es became correlated with each other. However, Ed and Es together with R decreased with an increase in moisture content up to fiber saturation point. Ed,  Es and R of tangile were significantly reduced by brashness at all designated moitsutre conditions. Under airdry condtition, Ed was approximately 10 and 12% higher than Es for normal tangile and apitong woods, respectively, while the difference for tangile brashwood was about 14%. Ed/Es ratio for each species increased with higher moisture content.