| Project/Area Number |
17K14762
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Building structures/Materials
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| Research Institution | Tokyo City University |
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Principal Investigator |
JIAO YU 東京都市大学, 建築都市デザイン学部, 准教授 (40632493)
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| Project Period (FY) |
2017-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2019: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2017: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
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| Keywords | 柱梁接合部 / 繰返し載荷実験 / 数値解析 / 低サイクル疲労 / 歪履歴 / 鋼構造 / 繰り返し載荷実験 / 亀裂長さ / 残存耐力 / 塑性変形能力 / Beam connections / Cyclic loading tests / Ductile fracture / Numerical analysis / Manson Coffin equation / 鋼構造柱梁接合部 / 有限要素法解析 / Manson-Coffin式 / 梁フランジ歪分布 / 応答解析 / 累積損傷度 / 部材面内解析 / 地震応答解析 / 連続地震 / 部材解析 / 載荷履歴 / 柱梁接合部実験 / 履歴モデル / 破断 |
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| Outline of Final Research Achievements |
Ductile fracture is one of the most typical steel component failure modes during earthquakes. For most structural steels, the strain-life relationship can be expressed using a Manson-Coffin-type equation. The current study proves whether there is a similar Manson-Coffin relationship between the average flange strain amplitude at the critical cross-section and the number of loading cycles until fracture. Shop welded beam-to-column connections made of 400 N/mm2 class structural steel with conventional or improved types of weld access holes are discussed in this study. Moreover, cyclic in-plane beam analysis is conducted to obtain the strain histories at the beam-end flanges. Based on the strain histories, it is found that, similar to the material level, the Manson-Coffin relationship between the average flange strain amplitude at the critical cross-section and the number of loading cycles until fracture is confirmed on the component level.
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| Academic Significance and Societal Importance of the Research Achievements |
梁降伏型骨組では、梁端接合部の塑性化により地震入力エネルギーを吸収する。梁端接合部の塑性変形能力を精度良く評価することが、骨組の耐震性能を正確に評価することに結びつく。梁部材の耐震性能を評価する際には、地震動及び構造物の特性を考慮した、振幅が小さいものから振幅が大きいものまで、様々な振幅を持つ載荷履歴の影響を考慮しなければならない。これまで梁の変形性能に関する研究では、変位振幅に着目したものがほとんどであり、本研究では、大振幅から長周期地震動を想定した弾性範囲に近い振幅が小さい繰り返し載荷履歴を受けた鉄骨梁の梁端フランジにおける歪振幅に着目し、歪振幅-繰返し回数（寿命）の関係を解明した。
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