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Study on Fatigue Strength Design of Welded-joint under random loading

Research Project

Project/Area Number 05452312
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 海洋工学
Research InstitutionUniversity of Tokyo

Principal Investigator

MACHIDA Susumu  Univ.of Tokyo, Faculty of Engineering, Professor, 大学院・工学系研究科, 教授 (70010692)

Co-Investigator(Kenkyū-buntansha) KANEDA Shigehiro  Univ.of Tokyo, Faculty of Engineering, Associate, 大学院・工学系研究科, 助手 (90010892)
YOSHINARI Hitoshi  Univ.of Tokyo, Faculty of Engineering, A.Professor, 大学院・工学系研究科, 助教授 (20167737)
新村 豊  東京大学, 工学部, 助手 (40010889)
小山 健夫  東京大学, 工学部, 教授 (10010696)
Project Period (FY) 1993 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥4,700,000 (Direct Cost: ¥4,700,000)
KeywordsStructual model specimen / "Storm Model" block loading / Fatigue assessment / The foatigue crack opening / closere phenomenon / "High-precision Compliance Mesurement System" / The effect of past loading history / Compliance / Change rate of compliance / RPG load
Research Abstract

The fatigue crack propagation tests using structural model specimens are carried out under constant loading and the "Storm Model" block loading. Also study on the reliability of the current fatigue assessment methods and the application of fracture mechanics to fatigue assesment are made.
Moreover, for the purpose of proper understanding of the fatigue crack opening/closure phenomenon, detailed observations of change in the strain near fatigue crack tip using "High-precision Compliance Measurement System" and CCT specimens are carried out.
As a result, the following four main points are obtained.
1) The fatigue assessment based on S-N diagram obtained from constant loading fatigue tests can not take into account the effect of past loading history. So the accuracy of this assessment turn out to be extremely lowered under some loading patterns. (for example, the loading pattern in which retardation is remarkable)
2) The fatigue assessment based on S-N diagram obtained form block loading fati … More gue tests can take into account the effect of the loading pattern within one block. So the accuracy of this assessment is higher than the above mentioned method 1) but it even can not take into account the effect of interaction of different block, then further high accuracy of this assessment depend on how quantitatively the block loading model reflects the actually loading pattern.
3) The fatigue assessment based on fracture mechanics can take into account the effect of past loading history, so the accuracy of this assessment could be higher than above mentioned method 2) if proper fatigue crack propagation model was established. Also further high accuracy of this assessment depend on proper understanding of the fatigue crack propagation behavior especially of the fatigue crack opening/closure phenomenon.
4) Successful measurement of the hysteresis curve of load vs.strain with high accuracy was made and, introducing the curve of compliance and the change rate of compliance during one cycle we succeeded in the automatically measurement of the Closing load and RPG load. Less

Report

(4 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • 1993 Annual Research Report
  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] 町田進: "ブロック荷重を受ける溶接構造の疲労寿命推定法に関する一考察" 日本造船学会論文集. 172. 579-587 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 林忠宏: "ランダム荷重下の疲労き裂伝播挙動に及ぼす荷重履歴の影響について" 日本造船学会論文集. 174. 523-533 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "溶接継手からの疲労き裂発生挙動に関する考察" 東京大学工学部総合試験所年報. 52. 71-77 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "疲労き裂先端歪み変化の詳細観察" 第8回破壊力学シンポジュウム講演論文集. 248-252 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "ランダム荷重疲労試験(曲げ)" 日本造船協会第216研究部会 平成4年度報告書. 228-233 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "嵐モデル変動荷重下の疲労試験(曲げ)" 日本造船協会第216研究部会 総合報告書. 289-297 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "荷重系列の影響" 日本造船協会第216部会 総合報告書. 407-409 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "き裂先端開閉口挙動(過大荷重の影響)" 日本造船協会第219研究部会 平成5年度報告書. 46-53 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "過大荷重下におけるき裂進展(その1)" 日本造船協会第219研究部会 平成6年度報告書. 44-57 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "スパイク荷重下におけるき裂進展" 日本造船協会第219研究部会 総合報告書. (予定). (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "従来き裂進展解析法による推定との比較" 日本造船協会第219研究部会 総合報告書. (予定). (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 町田進: "溶接継手からの疲労き裂発生に関する考察" 日本造船協会第220研究部会 平成6年度報告書. 143-144 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Concideration on Estimation of Welded Structure's Fatigue Life under Block Loading" JOURNAL OF THE SOCIETY OF NAVAL ARCHITECTS OF JAPAN. Vol.172. 579-589 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Chung-Hung Lin: "Fatigue Crack Propagation Behavior under Various Randam Amplitude Loading Condition" JOURNAL OF THE SOCIETY OF NAVAL ARCHITECTS OF JAPAN. Vol.174. 523-533 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Study on the Initiation of Fatigue Cracks at the Welded Toes" Annual Report of Engineering Research Institute Fuculty of Engineering University of Tokyo. Vol.52. 71-77 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Detailed Observation of Changes in Strain near Fatigue Crack Tip" Proceedings of The 8th Symposium on Fracture and Fracture Mechanics. 248-252 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Fatigue Test under Randam Loading" Japan Ship Research Report No.216 1992 Annual Report. 228-233 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Fatigue Test under modified Strain Loading" Japan Ship Research Report No.216 Final Report. 289-297 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Effects of Loading Series on Fatigue Behavior" Japan Ship Research Report No.216 Final Report. 407-409 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Crack Tip Opening and Closere (Effects of Over Loading)" Japan Ship Research Report No.219 1993 Annual Report. 46-53 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Crack Propagation under Over Loading (No.1)" Japan Ship Research Report No.219 1994 Annual Report. 44-57 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Crack Propagation under Spike Loading" Japan Ship Research Report No.219 Final Report. (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Fatigue Crack Propagation estimated from Conventional and New Methods" Japan Ship Research Report No.219 Final Report. (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Susumu Machida: "Consideration on Fatigue Crack Initiation from Welded Joints" Japan Ship Research Report No.220 1994 Annual Report. 143-144 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary

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Published: 1993-04-01   Modified: 2016-04-21  

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