| Project/Area Number |
17K06638
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Building structures/Materials
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| Research Institution | Nagoya University |
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Principal Investigator |
Yamasaki Mariko 名古屋大学, 生命農学研究科, 准教授 (70346170)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2019: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
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| Keywords | 経年使用木材 / 力学的耐久性 / 疲労試験 / エネルギー解析 / セルロース格子ひずみ / 残存寿命評価 |
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| Outline of Final Research Achievements |
The purpose of this study was to "clarify the deformation mechanism of wood during long-time use, and to evaluate the mechanical durability of aged wood as residual life". Test specimens were made from structural members used in the old temple during 200-250 years. From the micro behavior, the change of the mechanical properties of cellulose was examined, and the residual life was examined by the fatigue test as macro behavior.
As a result, it was indicated that some minute damage such as detachment between layers was caused in the secondary wall of the cell wall due to aging or long-time use. Because of such minute damage, the final energy of aged wood was lower than that of the recent wood, and the ratio of final energy to the envelope energy increased. In the case of tension, since the envelope energy is almost consumed during 250 years, it is suggested that the subsequent residual life in tension can be expressed by the transition of the final strain energy.
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| Academic Significance and Societal Importance of the Research Achievements |
木材における古材化の研究は，構造利用と文化財の両面からその意義が理解される．本研究の学術的意義は，古材の力学耐久性について，疲労試験によるエネルギー論的アプローチを用いた点と，木材バルクと細胞壁2次壁の各層のセルロース鎖の力学挙動を同時測定することで，古材化によって荷重伝達の遅れが生じることを見出した点にある．200年から250年使用された木材の場合，引張および曲げの力学耐久性は低下したが，曲げに対する低下の程度は引張ほど大きくない．一般に，木造建築の構造部材は曲げあるいは圧縮負荷を担うように配置されることが多く，これは力学的耐久性の観点からも理にかなった使用法である．
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