<departmental bulletin paper>
Some Availabilities of Lumbers from Sugi (Cryptomeria japonica) Tree Damaged by Typhoon

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Abstract 九州の台風被害木の基礎的材質が確かめられた.モメを含んだスギ材の標準曲げ試験の結果,曲げ破壊係数が正常材に比べ非常に低いものの,曲げヤング係数には大きな差は見られなかった.同時に測定されたAEの発生は,正常材では比例限度応力以降に見られたが,モメを含む場合負荷開始時点から発生が認められた.モメが生じている丸太横断面内の強度性能分布が調査された.曲げ破壊係数と比例限度応力はモメ発生位置と同様な分布を...示すが,タッピング法および曲げ試験におけるヤング係数の分布はモメの分布とは無関係であった.平割材の材長方向のモメ発生分布とE_sp(見かけの曲げヤング係数〉の分布との対応が調査された.その結果,曲げ応力が大きいほど,また,材厚が薄く断面内のモメの割合が増すほど,モメ発生位置との対応が見られた.モメを含む接着面の接着せん断試験が行われた.木破率はキメを含まないものと差ほ見られなかったが,接着せん断強さは有意な低下が見られた.
This paper is concerned with the availability of sugi wood damaged by the serious typhoon in Kyushu Island. The following results were obtained ; 1. In bending test, the MOR of the lumber with some partial compression failures (mome) was obviously smaller than that free from such a damage, however, the MOE of the former was almost the same as that of the latter. 2. In AE monitoring in bending test, AE signals of lumber free from the damage generated over the proportional limit of load-deformation diagram, but those of lumber with mome developed directly after the beginning of bending. 3. As was evident from the observation of the cross-sectional distributions of bending properties of lumber with mome, the localization of mome was similar not to both the distributions of the MOE in the static test and the tapping method but clearly to both the distributions of the MOR and the stress at proportional limit. 4. By the middle ordinate method under an uniform bending moment throughout the whole span of lumber, the significant correspondence could be observed between the localization of mome and the MOE along the length of lumber. Especially, it was certain that presence of mome more than 50% ratio to the whole cross section caused a low value evidently for the localized MOE. 5. There was significant difference not in wood failure, but surely in bonding strength between both the glue lines of lamina with mome and that free from mome.
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Created Date 2009.04.22
Modified Date 2021.03.03

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