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Micromechanics for Random System and Its Application to Small Crack Problems

Research Project

Project/Area Number 11650090
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Materials/Mechanics of materials
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

TOSHIHIKO Hoshide  Kyoto University, Graduate School of Energy Science, Associate Professor, エネルギー科学研究科, 助教授 (80135623)

Project Period (FY) 1999 – 2000
Project Status Completed (Fiscal Year 2000)
Budget Amount *help
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
KeywordsRandom system / Micromechanics / Small crack / Microstructure / Crystalline orientation / Grain morphology / Fracture / Fatigue / 結晶粒径 / 欠陥寸法 / 多結晶材料
Research Abstract

1. Analysis of Strength Characteristic by Considering Random Microstructure in Ceramics : The modification factor for the stress intensity factor was derived as a new mechanical parameter in a random system so that the influence of microstructures in ceramic could be reflected in the parameter. To evaluate the modification factor, numerical analyses on the crack-tip stress field were conducted by taking account of variations in the stiffness and size of individual grains as the difference of microstructures. The stress filed was significantly affected by the stiffness of grains around the grain at the crack-tip, but hardly influenced by the grain-size. The modification factor obtained from the aforementioned analyses was found to become smaller for a longer crack length. Using the simulated distribution of the modification factor, the strength distribution was estimated based on the criterion using the resistance curve concept. The estimated strength distribution was able to show an average tendency in experimental results well.
2. Analysis of Fatigue Characteristic by Considering Random Microstructures in Metallic Materials : Deformed hexagons were adopted as elements in modeling metallic polycrys-talline materials. In modeling a microstructure with two phases, the phases were selected from elements by using random numbers so that the selection should correspond to the proportion of each phase occupied in the microstructure. For polycrystalline materials composed of such elements, a crack growth model was constructed based on the competition between the linkage mode of initiated cracks and by the propagation mode of an individual crack. Using the model, notched components for four kinds of metallic materials with different microstructures under multiaxial fatigue were statistically simulated by using a Monte Carlo procedure. It was shown that the distribution range of the simulated life sufficiently covered the failure life observed experimentally.

Report

(3 results)
  • 2000 Annual Research Report   Final Research Report Summary
  • 1999 Annual Research Report
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Toshihiko Hoshide: "Characterization of Integrated Data on Inherent Flaws in Engineering Ceramics"Materials Science Research International. 5. 285-290 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Toshihiko Hoshide: "A Microstructural Approach to Flaw Size Dependence of Strength in Engineering Ceramics"Fatigue & Fracture of Engineering Materials & Structures. 22. 1029-1039 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Toshihiko Hoshide: "Statistical Properties Fatigue Life Simulated for Notched Components under Combined Loading"JSME International Journal, Series A. 43. 210-219 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Toshihiko Hoshide: "Characterization of Integrated Data on Inberent Flaws in Engineering Ceramics"Mater.Sc.Res.Int.. Vol. 5. 285-290 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Toshihiko Hoshide: "A Microstructural Approach to Flaw Size Dependence of Strength in Engineering Ceramics"Fatigue Fract.Eng.Mater.Struct.. Vol. 22. 1029-1039 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Toshihiko Hoshide: "Statistical Properties Fatigue Life Simulated for Notched Components under Combined Loading"JSME Int.J., Series A. Vol.43. 210-219 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Toshihiko Hoshide: "Statistical Properties Fatigue Life Simulated for Notched Components under Combined Loading"JSME International Journal Series A. 43. 210-219 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Toshihiko HOSHIDE: "A Microstructural Approach to Flaw Size Dependence of Strength in Engineering Ceramics"Fatigue Fract.Engng Mater.Struct.. 22-12. 1029-1039 (1999)

    • Related Report
      1999 Annual Research Report

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Published: 2000-04-01   Modified: 2016-04-21  

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