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Prediction of Ultimate Strength Determined by Brittle Fracture Initiating from Weld Defects - Quality Control Criterion of the Connections

Research Project

Project/Area Number 16K06595
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Building structures/Materials
Research InstitutionSojo University

Principal Investigator

AZUMA Koji  崇城大学, 工学部, 教授 (80320414)

Co-Investigator(Kenkyū-buntansha) 岩下 勉  有明工業高等専門学校, 創造工学科, 教授 (10332090)
Project Period (FY) 2016-04-01 – 2019-03-31
Project Status Completed (Fiscal Year 2018)
Budget Amount *help
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywords脆性破壊 / 延性き裂 / 溶接欠陥 / 破壊靱性 / 塑性拘束 / 破壊評価 / 終局耐力 / スカラップ / スカラップ底 / 有限要素解析 / 破壊靭性 / 機械切欠き / 建築構造・材料 / 鋼構造 / 溶接接合部
Outline of Final Research Achievements

This paper concerns the applicability of the Weibull stress approach for prediction of brittle fracture initiated at the root of welds. Beam-to-diaphragm joint models, which were designed to represent a connection of beam-to-column joint with through diaphragms, were tested under cyclic loads. The load was applied to the end of the cantilever by a hydraulic ram cyclically. Specimens had those discontinuities at the roots of welds to the diaphragm. Through cracks were installed on both sides of weld terminations. The prediction of brittle fracture with a variety of defect sizes by using the FE analysis was conducted. The applicability of the Weibull stress approach, comparing it with the applicability of the TSM approach, in predicting brittle fracture from such defects was verified. Furthermore, the effect that the shape of weld access hole gives to ultimate strength of specimens was examined, because the brittle fracture occurred from the toes of weld access hole of some specimens.

Academic Significance and Societal Importance of the Research Achievements

造船や溶接の分野では古くから脆性破壊に関する研究が行われており,材料強度学として一つの体系をなしている.塑性変形能力に期待する耐震設計において,最も避けたい破壊形式であるが,近年,建築分野ではこの種の研究が減少している.兵庫県南部地震直後には,鋼構造建物の柱梁接合部における脆性破壊が注目され,数多くの防止策の検討がなされ,破壊評価手法が策定されたが,延性き裂の影響を考慮したものは未だに確立されていない.今後,予想される巨大地震が発生する前に,この点を解決した評価方法を確立することは,建物の安全性を担保する上で,大きな意義がある.

Report

(4 results)
  • 2018 Annual Research Report   Final Research Report ( PDF )
  • 2017 Research-status Report
  • 2016 Research-status Report
  • Research Products

    (12 results)

All 2019 2018 2017

All Journal Article (2 results) (of which Peer Reviewed: 2 results) Presentation (10 results) (of which Int'l Joint Research: 6 results)

  • [Journal Article] 切欠きから延性き裂を伴って発生する脆性破壊の損傷度2018

    • Author(s)
      岩下 勉,松田郁哉,東 康二
    • Journal Title

      鋼構造年次論文報告集

      Volume: 26 Pages: 709-715

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed
  • [Journal Article] 溶接 H 形鋼の加熱矯正工程の作業効率向上と鋼材特性に関する報告2018

    • Author(s)
      安田匠汰,東 康二,板谷俊臣,中村洋一,村山将広
    • Journal Title

      鋼構造年次論文報告集

      Volume: 26 Pages: 456-461

    • Related Report
      2018 Annual Research Report
    • Peer Reviewed
  • [Presentation] 繰返し負荷を受ける切欠きを有する鋼試験片の脆性破壊発生に関する研究 -破壊靱性の違いによる考察-2019

    • Author(s)
      松田郁哉,岩下勉,東康二
    • Organizer
      2018年度日本建築学会九州支部研究報告
    • Related Report
      2018 Annual Research Report
  • [Presentation] Prediction of brittle fracture of at the Toes of Weld Access Hole of the welded I-section Beam End2019

    • Author(s)
      Junwei Wang, Koji Azuma, Tsutomu Iwashita, Toshiomi Itatani
    • Organizer
      29th Int. Offshore and Polar Engineering Conf.
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Prediction of Brittle Fracture at the Crack tips of Improved Weld Access Hole of Full-scale Beam-to-Column Assembly2019

    • Author(s)
      Satoshi Jimbo, Koji Azuma, Toshiomi Itatani, Masato Nikaido
    • Organizer
      29th Int. Offshore and Polar Engineering Conf.
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Prediction of Brittle Fracture from Notches at the Toes of Butt Weld and Weld Access Hole of the Beam End2018

    • Author(s)
      Azuma K., Akahoshi T., Iwashita T., Itatani, T.
    • Organizer
      International Institute of Welding
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 繰返し載荷を受ける切欠きを有する鋼試験片の塑性変形能力に関する研究 その5 ワイブル応力を用いた変形能力推定方法の検討2018

    • Author(s)
      岩下 勉,東 康二
    • Organizer
      2018年度日本建築学会大会学術講演会
    • Related Report
      2018 Annual Research Report
  • [Presentation] Effects of Cyclic Loading on Brittle Fracture in Steel Notched Specimens with Different Fracture Toughness2017

    • Author(s)
      Iwashita, T., Azuma, K.
    • Organizer
      14th International Conference on Fracture
    • Place of Presentation
      Rhodes, Greece
    • Year and Date
      2017-06-18
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Presentation] Effects of Cyclic Loading on Brittle Fracture in Steel Notched Specimens with Different Toughness2017

    • Author(s)
      Iwashita, T., Azuma, K.
    • Organizer
      14th International Conference on Fracture
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research
  • [Presentation] Cumulative Damage of Notched Specimens with Brittle Fracture under Cyclic Loading2017

    • Author(s)
      Iwashita, T., Tateno, A., Azuma. K.
    • Organizer
      16th International Symposium on Tubular Structures
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research
  • [Presentation] 繰返し載荷を受ける切欠きを有する鋼試験片の塑性変形能力に関する研究 その3 損傷度と延性き裂進展の検討2017

    • Author(s)
      岩下勉,小宮慎二,立野文,東康二
    • Organizer
      2017年度日本建築学会大会
    • Related Report
      2017 Research-status Report
  • [Presentation] 繰返し載荷を受ける切欠きを有する鋼試験片の塑性変形能力に関する研究 その4 ワイブル応力による検討2017

    • Author(s)
      小宮慎二,岩下勉,東康二
    • Organizer
      2017年度日本建築学会大会
    • Related Report
      2017 Research-status Report

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Published: 2016-04-21   Modified: 2020-03-30  

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