Analysis of Large Deformation in Wood Using Fast Fourier Transform Method
| Project/Area Number |
07660220
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
NORIMOTO Misato Kyoto Univ., Wood Res.Inst., Prof., 木質科学研究所, 教授 (20027163)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Hast Fourier Transform Method / Power Spectrum / Replica Method / Cell Model / Shrinkage / Shrinkage Anisotropy / Wood / Compression Wood / 横圧縮変形 / レプリカ |
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| Research Abstract |
The large shrinkage deformation of the normal wood of five kinds of conifers (Cryptomeria japonica, Chamaecyparis obtusa, Picea sitchensis, Agathisbornensis, Pinus radata) and compression wood of two kinds of conifers (C.japonica, C.obtusa) in the transverse direction was analyzed using the replica and Fast Fourier Transform methods. A wood specimen was pushed on a polyethylene film softened by heating to obtain the replica. The replicas obtained were subjected to the power spectrum analysis. The representative cell models before and after shrinkage were constructed by the power spectrum analysis. During drying, cell lumens shrunk in normal wood and expaded in compression wood, depending on their cell wall structures. The tracheids of A.bornensis with no distinct growth rings also showed the anisotropic shrinkage. The included angle between two radaial walls for the model with a hexagonal shape became larger during shrinkage, which incresed the shrinkage in the tangential direction. The difference in anisotropic shrinkage among wood species greatly depended on their transverse cell shapes, that is, the shrinkage anisotropy was larger in cells (C.obtusa) with a hexagonal shape than in those (P.sitchensis) with a rectangular shape. Equations that express the redial and tangential shrinkages were derived using a model composed of late and early wood, and shrinkage anisotropy as a function of the late wood fraction was predicted. The shrinkages of early wood and late wood for P.radiata were calculated using the representative cell models. The values of eraly wood in the radial and tangential directions were 2.52% and 5.46%, and those of late wood were 7.23% and 8.01%, respectively. The calculated value of the ratio of the Young's modulus of early wood to that of wood in the tangential direction was 0.812, which agreed well with an experiment value of 0.881. The shrinkage anisotropy depended significantly on the mechanical interaction between early wood and late wood.
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Report
(3 results)
Research Products
(9 results)
