Influence of Moisture Content on Some Elastic Constants of Black Pine Subjected to Compression
2017
Ergun GUNTEKIN | Seda DEMIRATLI
Moisture content is an important factor influencing physical and mechanical behaviors of wood materials. This research aimed at quantifying effect of moisture content on some orthotropic mechanical properties of Black pine wood. The elastic properties investigated include EL, ER, ET, ʋLR, ʋLT, ʋRL, ʋRT, ʋTL and ʋTR under compression. Compression strength in all orthotropic directions was also studied. Specimens were cut from sapwood of pine logs and sorted into four matched MC groups. Clear wood samples were conditioned at 20°C and 45%, 65%, 85%, 95% RH and subjected to compression tests. A bi axial extensometer was used to measure active and passive strain during loading. Young modulus, Poisson ratios, and compression strength were calculated and compared for all orthotropic directions. Results indicated that elastic and strength properties are significantly different in principal directions. Both Young’s modulus and compression strength of the samples tested were strongly affected by moisture content. Both properties decrease seemingly linear with increasing moisture content. Poisson ratios seem to be insensitive to the MC changes.
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