| Project/Area Number |
17K06629
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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 | Chiba University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2018: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | 建築構造・材料 / 鋼構造 / 低サイクル疲労 |
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| Outline of Final Research Achievements |
According to a previous research review on low-cycle fatigue performance of steel structures, it was found that the low-cycle fatigue lives under constant amplitude and the cumulative damage indices under variable amplitudes were log-normally distributed and that their coefficients of variation were approximately 10% and 30%, respectively. The low-cycle fatigue tests of the welded joints under shear strain were conducted, and the results revealed that the fatigue performance under shear could be evaluated from the fatigue curve under normal strain by converting the shear strain to an equivalent normal strain. The assessment method of fatigue failure probabilities of beam-ends in steel building structures was proposed, by combining the seismic response analysis of the frame model with fiber elements and the finite element analysis of 3D solid models of beam-end portions, which provided the relation between macro and local strain (fiber element's and hot-spot strain) at the beam-end.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では、溶接継手レベルの低サイクル疲労性能と数値シミュレーション(有限要素解析・骨組応答解析)を組み合わせることで鉄骨架構内の全ての梁端での疲労破壊発生確率を推定する手法を提示した。同手法の最大の利点は、必要な実験データが溶接継手レベルの低サイクル疲労性能のみで、部材・架構レベルでの大規模な構造実験が不要なことである。さらに、数値シミュレーション部分の精緻化によってさらなる高精度の信頼性評価ができる拡張性の高さも同手法の特色である。本研究の手法によって梁端ごとの破壊確率を得られれば、高層鉄骨架構の合理的な補強方法の検討に活用することができるだろう。
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