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Crack progress characteristic of steel in air and corrosive environment

Research Project

Project/Area Number 09450178
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 構造工学・地震工学
Research InstitutionDaido Institute of Technology

Principal Investigator

KOTOGUCHI Hisao  Daido Institute of Technology,Engineering, Professor, 工学部, 教授 (60047305)

Co-Investigator(Kenkyū-buntansha) MIKI Toshihiro  Daido Institute of Technology,Engineering, Professor, 工学部, 教授 (90137175)
MIZUSAWA Tomisaku  Daido Institute of Technology,Engineering, Professor, 工学部, 教授 (60113081)
Project Period (FY) 1997 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥2,600,000 (Direct Cost: ¥2,600,000)
KeywordsFracture mechanics / Crack progress / Corrosive environment / Fluctuating load / 疲労破面 / き烈進展 / 両振り
Research Abstract

3)Crack progress characteristic of two stage fluctuating load (1) The crack opening and closing stress at an excessive load at the fluctuating load decreases compared with that of the constant load examination. (2) That is, the crack opening and closing stress at a high-level load is ruled by the correspond stress at a low-level load. (3) At the fluctuating load, there are a lot of progressing cracks of the crystal grain field compared with the constant load. This could be confirmed from the SEM observation.
2)Micro-rack behavior of steel under salt water environment (1) The different of the load level remarkably influenced the crack progress behavior under the salt-water environment. (2) The micro-crack area does not exist under the corrosive environment when the load is small either. (3) The crack generation time is controlled by the stress condition under the salt-water environment , the crack progress driving force accounts for 85% of the full load. On the other hand, it was about 75% under an atmospheric environment. That is, the crack growth rate becomes early under the salt-water environment.
The research results are as follows:
1) Crack progress characteristic of single and both sides' amplitude (1) When stress ratio R is R>O region, the crack growth rate quickens because the crack progress driving force increases as R increases. (2) For stress ratio<O region,the crack opening and closing stress is corresponding to a neutral stress of the load. (3) All amplitudes in the tension side work as crack progress driving force. (4) There is a straight-line relation between the value of the crack opening and closing stress/the total amplitude stress and the stress ratio R.

Report

(4 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • 1997 Annual Research Report
  • Research Products

    (23 results)

All Other

All Publications (23 results)

  • [Publications] 事口壽男: "変動荷重における鋼のき裂進展"土木学会中部支部研究発表会講演概要集. 65-66 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 事口壽男: "変動荷重におけるき裂進展"土木学会53回年次学術講演会講演概要集. 1-A. 596-597 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hisao Kotoguchi: "Some aspects of small fatigue cracks under variable stress ratios"ECF-12 Fracture from Defects : The conference Proceedings. 12th, Vol.1. 283-288 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 事口壽男: "変動荷重による鋼の微視き裂"土木学会中部支部研究発表会講演概要集. 65-66 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 事口壽男: "片振りと両振りにおける鋼のき裂進展"土木学会第52回年次学術講演会概要集. 1-A. 448-449 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hisao Kotoguchi and H.Okamoto: "Crack progress characteristic of simple and both sides'amplitude"Outline thesis collection of JSCE 52th. 1-A. 448-449 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hisao Kotoguchi and H.Okamoto: "Micro-crack of steel in fluctuating load"Outline thesis collection of JSCE,Tyubu branch. 65-66 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hisao Kotoguchi: "Some aspect of small fatigue cracks under variable stress ratio"FCF-12 Fracture from Defect,The conferrence Proceeding. Vol.1. 283-288 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hisao Kotoguchiand Takayuki Wakasugi: "Crack progress in fluctuating load"Outline thesis collection of JSCE 53th. 1-A. 596-597 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Hisao Kotoguchi and Takayuki Wakasugi: "Crack progress in fluctuating load"Outline thesis collection of JSCE,Tyubu branch. 65-66 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 事口壽男: "変動荷重における鋼のき裂進展"土木学会中部支部研究発表会講演概要集. 65-66 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] 事口壽男: "変動荷重におけるき裂進展"土木学会53回年次学術講演会講演概要集. 1-A. 596-597 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] Hisao Kotoguchi: "Some aspects of small fatigue cracks under variable stress ratios"ECF-12 Fracture from Defects:The conference Proceedings. 12th,Vol1. 283-288 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] 事口壽男: "変動荷重による鋼の微視き裂"土木学会中部支部研究発表会講演概要集. 65-66 (1998)

    • Related Report
      1999 Annual Research Report
  • [Publications] 事口壽男: "片振りと両振りにおける鋼のき裂進展"土木学会第52回年次学術講演会講演概要集. 1-A. 448-449 (1997)

    • Related Report
      1999 Annual Research Report
  • [Publications] 事口壽男: "片振りと両振りにおける鋼のき裂進展" 土木学会第52回年次学術講演会講演概要集. 1-A. 448-449 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] 事口壽男: "変動荷重による鋼の微視き裂" 土木学会中部支部研究発表会講演概要集. 65-66 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] Hisao Kotoguchi: "Some aspects of small fatigue cracks under variable stress ratios" ECF-12-Francture from Defects : The Conference Proceedings. 12^<th>,vol1. 283-288 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] 事口壽男: "変動荷重における鋼のき裂進展" 土木学会第53回年次学術講演会講演概要集. 1-A. 596-597 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] 事口壽男: "変動荷重における鋼のき裂進展" 土木学会中部支部研究発表会講演概要集. 65-66 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] 事口壽男: "片降りと両振りにおける鋼のき裂進展" 土木学会第52回年次学術講演会講演概要集. 1-A. 448-449 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 事口壽男: "変動荷重による鋼の微視き裂" 土木学会中央支部研究発表会講演概要集. 65-66 (1998)

    • Related Report
      1997 Annual Research Report
  • [Publications] Hisao Kotoguchi: "Some aspects of small fatigue cracks under variable atress ratios" ECF-12-Fracture from Defects : The Conference Proceedings. Announcement schedule. (1998)

    • Related Report
      1997 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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