Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0-95°C : hardwood vs. softwood and normal wood vs. reaction wood
| Autor: | Joëlle Passard, Patrick Perré, Vincent Placet |
|---|---|
| Přispěvatelé: | Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Etude et de Recherche sur le Matériau Bois (LERMAB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université Henri Poincaré - Nancy 1 (UHP) |
| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
0106 biological sciences
Materials science Softwood Softening point reaction wood FOS: Physical sciences Physics - Classical Physics anisotropy 01 natural sciences Viscoelasticity [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph] Biomaterials 010608 biotechnology [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] Hardwood Green wood time-temperature equivalence Composite material Anisotropy viscoelasticity ComputingMilieux_MISCELLANEOUS 040101 forestry Classical Physics (physics.class-ph) 04 agricultural and veterinary sciences Dynamic mechanical analysis [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] Compression (physics) dynamic mechanical analysis (DMA) 0401 agriculture forestry and fisheries Cole-Cole diagrams environmental vibration analyser for wood (WAVET) |
| Zdroj: | Holzforschung Holzforschung, De Gruyter, 2007, 61 (5), pp.548-557 Holzforschung, De Gruyter, 2007, 61, pp.548-557. ⟨10.1515/HF.2007.093⟩ |
| ISSN: | 0018-3830 1437-434X |
| Popis: | The viscoelastic properties of wood have been investigated with a dynamic mechanical analyser specifically developed for wooden materials, the WAVET device. Measurements were carried out on four wood species in the temperature range 0–100°C at frequencies varying between 5 mHz and 10 Hz. Wood samples were tested under water-saturated conditions in the radial and tangential directions. As expected, the radial direction always revealed a higher storage modulus than the tangential direction. Great differences were also observed in the loss factor. The tanδ peak and internal friction were higher in the tangential than in the radial direction. This behaviour is attributed to the fact that anatomical elements act as a function of the direction. The viscoelastic behaviour of reaction wood differs from that of normal or opposite wood. Compression wood of spruce, which has a higher lignin content, is denser and stiffer in transverse directions than normal wood, and has a lower softening temperature (T g). In tension wood, the G-layer is weakly attached to the rest of the wall layers. This may explain why the storage modulus and softening temperature of tension wood are lower than those for opposite wood. We also demonstrate that the time-temperature equivalence fits only around the transition region, i.e., between T g and T g+30°C. Apart from these regions, the response of wood reflects the combined effects of all its constitutive polymers, so that the equivalence is no longer valid. |
| Databáze: | OpenAIRE |
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