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Study on Fatigue Crack Growth Behavior of Small and Long Cracks at Elevated Temperatures

Research Project

Project/Area Number 60460081
Research Category

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

Allocation TypeSingle-year Grants
Research Field 材料力学
Research InstitutionOsaka University

Principal Investigator

OGURA Keiji  Professor,Faculty of Engineering Science, Osaka University, 基礎工学部, 教授 (70029007)

Co-Investigator(Kenkyū-buntansha) NISHIKAWA Izuru  Research Associate, Faculy-of Engineering Science, Osaka University, 基礎工学部, 助手 (90189267)
MIYOSHI Yoshio  Associate Professor, Faculty of Engineering Science, Osaka University, 基礎工学部, 助教授 (40029434)
Project Period (FY) 1985 – 1987
Project Status Completed (Fiscal Year 1987)
Budget Amount *help
¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
KeywordsFatigue Crack Growth / Crack Closure / Fatigue Threshold / %elveated Temerature / Oxide / Fractre Surface Roughness / 破面あらさ / 不活性環境 / 進展下限界 / 付着酸化物
Research Abstract

Fatigue crack growth (FCG) was investigated at elevated temperatures up to 500゜C. The emphasis was made on examining the role of crack closure on the near threshold FCG behAvior at elevated temperatures. FCG tests were made on the samples of low carbon steels (SM41A and SS41), a stainless steel (SUS304) and an aluminum alloy (A2218-T6) in air environment. Some additional tests were made in SM41A and SUS304 in Ar gas in order to examine the effect of oxidation ot the FCG behavior. The results are summarized as follows.
(1) The FCG rate was accelerated at elevated temeratures at far threshold or higher <delta><kappa> region.
(2) The FCG rate, on the other hand, was decelerated at elevated temperatures near threshold region, and the fatigue threshold, <delta><kappa>th, increased with increase in temperature in air environment.
(3) The increase in <delta><kappa>th at elevated temperatures was found to be caused both by the enhanced crack closure due to the oxide products induced on the fracture surface and the increase in <delta><kappa>eff.th, the intrinsic FCG resistance of the material.
(4) The contcibution of the crack closure to the increase in <delta><kappa>th was different for different materials. The crack closure was an important role on the increase in <delta><kappa>th in SM41A, but it was a less important role in SUS304.
(5) Much increase in <delta><kappa>eff.th in SUS304 was observed in air environment in comparison withe the value in Ar gas at 300゜C. The intrinsic FCG resistance itself was found to be much influened by oxdation in this material, although the detail mechanisms is still unknown.
(6) It was concluded that the oxide products could contribute to the increase in <delta><kappa>th only when the relative thickness of the crack tip opening displacement memained small.

Report

(2 results)
  • 1987 Final Research Report Summary
  • 1986 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] 小倉敬二: 日本機械学会論文集. 52. 89-98 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] 西川出: 日本機械学会論文集. 52. 1269-1275 (1988)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] 西川出: 日本機械学会論文集. 53. 993-999 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] 小倉敬二: 第4回破壊力学シンポジウム(日本材料学会). 11-15 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Izuru Nishikawa: JSME International Journal(日本機械学会). 31. 92-99 (1988)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Keiji Ogura: VI Internatinal Congress on Experimental Mechanics. (1988)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Keiji,Ogura: "Fatigue Crack Growth and Threshold Behavior at Elevated Temperatures" Transactions of the Japan Society of Mechanical Engineering. 52. 89-98 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Izuru,Nishikawa: "Effect of Oxide and Roughness on Fatigue Crack Growht Threshold in Low Xarbon Steel at Elevated Temerature" Transactions of the Japan Society of Mechanical Engineeing. 52. 1269-1275 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Izuru,Nishikawa: "The Role of Crack Closure in the Fatigue Threshold at Elevated Temperatures" JSME International Journal. 31. 92-99 (1988)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Keiji,Ogura: "The Influence of Temperature on the Near-threshold Fatigue Crack Growth Rate of SUS304 and SM41A Steel" Intecnational Conference on role of Fracture Mechanics in Modern Technology, Hakata. 137- (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] Kiji,Ogura: "Crack Closure Measurement and Fatigue Threshold in the Temperature range between -100 and 500゜C" VI International Congress on Experimental Mechanics. (1988)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1987 Final Research Report Summary
  • [Publications] 小倉敬二: 日本機械学会論文集. 52. 89-98 (1986)

    • Related Report
      1986 Annual Research Report
  • [Publications] 西川出: 日本機械学会論文集. 52. 1269-1275 (1986)

    • Related Report
      1986 Annual Research Report
  • [Publications] 西川出: 日本機械学会論文集. 53. (1987)

    • Related Report
      1986 Annual Research Report
  • [Publications] KeijI Ogura: Abstracts of Inte.Conf.on Role of Fracture Mechanics in Mordern Technology(FuKuoka,Japan). 137 (1986)

    • Related Report
      1986 Annual Research Report
  • [Publications] 西川出: 第18回被労シンポジウム(日本材料学会). 196-200 (1986)

    • Related Report
      1986 Annual Research Report
  • [Publications] 西川出: 第4回破壊力学シンポジウム(日本材料科学会). (1987)

    • Related Report
      1986 Annual Research Report

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Published: 1987-03-31   Modified: 2016-04-21  

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