Modelling of the hygroelastic behaviour of normal and compression wood tracheids |
| |
| Affiliation: | 1. Uppsala University, Department of Engineering Sciences, Ångström Laboratory, Box 534, SE-751 21 Uppsala, Sweden;2. Laboratoire de Technologie des Composites et Polymères (LTC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland;3. SP Technical Research Institute of Sweden, SP Wood Technology, P.O. Box 5609, SE-114 86 Stockholm, Sweden;1. UMR7245 CNRS-MNHN Molécules de Communication et Adaptation des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France;2. Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55, PL-00-818 Warszawa, Poland;3. UMR7159 ISPL-LOCEAN, Institut de Recherche pour le Développement, Bondy, France;4. The Laboratory for Molecular Marine Ecology (LMME) Bar-Ilan University, Ramat-Gan, Israel;5. Department of Environmental Sciences, The Weizmann Institute of Sciences, Rehovot, Israel;6. Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland;1. Mechanics and Materials Processing Dept, Lab. G. Friedel UMR CNRS 5307, Mines Saint-Étienne, 158 Cours Fauriel CS 62362, 42023 Saint-Étienne, France;2. Department of Materials Engineering (MTM), KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven, Belgium;1. Institute for Applied Materials (IAM-WK), Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany;2. Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, 721302, India;3. Matworks GmbH, Gartenstrasse 133, Aalen, 73430, Germany;4. Institute of Materials Resource Management, University of Augsburg, Augsburg, 86135, Germany;1. Chair of Computational Mechanics, Bauhaus Universität Weimar, Marienstraße 15, 99423 Weimar, Germany;2. Composites Research Laboratory, Faculty of New Sciences & Technologies, University of Tehran, Tehran 1439955941, Iran;3. Department of Geotechnical Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China;1. Assoc. Professor-ME Deptt.,Inderprastha Engineering College,Ghaziabad-201005 Delhi NCR, India;2. Assoc. Professor-ME Deptt.,School Of Engineering, Gautam Buddha University,Gautam Buddha Nagar, Delhi NCR, India;3. Asstt. Professor-ME Deptt.,School Of Engineering, Gautam Buddha University,Gautam Buddha Nagar,Delhi NCR, India |
| |
| Abstract: | Compression wood conifer tracheids show different swelling and stiffness properties than those of usual normal wood, which has a practical function in the living plant: when a conifer shoot is moved from its vertical position, compression wood is formed in the under part of the shoot. The growth rate of the compression wood is faster than in the upper part resulting in a renewed horizontal growth. The actuating and load-carrying function of the compression wood is addressed, on the basis of its special ultrastructure and shape of the tracheids. As a first step, a quantitative model is developed to predict the difference of moisture-induced expansion and axial stiffness between normal wood and compression wood. The model is based on a state space approach using concentric cylinders with anisotropic helical structure for each cell-wall layer, whose hygroelastic properties are in turn determined by a self-consistent concentric cylinder assemblage of the constituent wood polymers. The predicted properties compare well with experimental results found in the literature. Significant differences in both stiffness and hygroexpansion are found for normal and compression wood, primarily due to the large difference in microfibril angle and lignin content. On the basis of these numerical results, some functional arguments for the reason of high microfibril angle, high lignin content and cylindrical structure of compression wood tracheids are supported. |
| |
| Keywords: | Compression wood Reaction wood Dimensional stability Hygroelastic properties Modelling |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
