Radial variations of vibrational properties of three tropical woods

The radial trends of vibrational properties, represented by the specifi c dynamic modulus (E /?) and damping coeffi cient (tan ?), were investigated for three tropical rainforest hardwood species (Simarouba amara, Carapa procera, and Symphonia globulifera) using free-free fl exural vibration tests. The microfi bril angle (MFA) was estimated using X-ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E /? was found to decrease from pith to bark, which was strongly related to the increasing pith-bark trend of MFA. The variation of tan ? along the radius could be partly explained by MFA and partly by the gradient of extractives due to heartwood formation. The coupling effect of MFA and extractives could be separated through analysis of the log(tan ?) versus log(E /?) diagram. For the species studied, the extractive content putatively associated with heartwood formation generally tends to decrease the wood damping coeffi cient. However, this weakening effect of extractives was not observed for the inner part of the heartwood, suggesting that the mechanical action of extractives was reduced during their chemical ageing.

Bibliographic Details

Main Authors:	Zhang, Tian, Shu-Lin Bai, Bardet, Sandrine, Alméras, Tancrède, Thibaut, Bernard, Beahchene, Jacques
Format:	article biblioteca
Language:	eng
Subjects:	K50 - Technologie des produits forestiers, bois, propriété technologique, vibration, quassia, Meliaceae, Symphonia, bois tropical, http://aims.fao.org/aos/agrovoc/c_8421, http://aims.fao.org/aos/agrovoc/c_2572, http://aims.fao.org/aos/agrovoc/c_8211, http://aims.fao.org/aos/agrovoc/c_35698, http://aims.fao.org/aos/agrovoc/c_4716, http://aims.fao.org/aos/agrovoc/c_33891, http://aims.fao.org/aos/agrovoc/c_293007aa,
Online Access:	http://agritrop.cirad.fr/563000/ http://agritrop.cirad.fr/563000/1/document_563000.pdf
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