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Studies on Dislocation Dynamical Model having an Emitting Source at a Crack Tip on Supposition of Crack Propagation

Research Project

Project/Area Number 05650081
Research Category

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

Allocation TypeSingle-year Grants
Research Field Materials/Mechanics of materials
Research InstitutionKyoto Institute of Technology

Principal Investigator

SAITO Kenji  Kyoto Institute of Technology, Mechanical and System Engineering, Professor, 工芸学部, 教授 (20027775)

Co-Investigator(Kenkyū-buntansha) ARAKI Shigetoshi  KIT,Mechanical and System Engineering, Research Associate, 工芸学部, 助手 (60222741)
IWAMOTO Masaharu  KIT,Mechanical and System Engineering, Professor, 工芸学部, 教授 (70089861)
Project Period (FY) 1993 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1993: ¥1,500,000 (Direct Cost: ¥1,500,000)
KeywordsDislocation dynamics / Criteria for the emission of dislocations / Crack / Inclusion / Critical stress intensity factor / Pile-up / Fatigue crack growth / Crack opening displacement / CTOD
Research Abstract

The present research deals with the analysis of the interaction between a crack and an inclusion from the standpoint of the dynamics of dislocations which are emitted from the crack tip and pile up against an inclusion. The criteria for emission of dislocations are assumed to be governed by the local stress intensity factor at the crack tip. The equations of motions for dislocations can be obtained by considering the swelling of the applied stress due to the inclusion, image dislocations in it, and the interactions between a crack and dislocations. The effects of the rigidity and the radius of the inclusion, etc., on the shear strain near the inclusion can be evaluated.
In addition to this, in order to determine the effect of the orientation of crystal grains on the fatigue crack growth, the analysis of the model that edge dislocations emitted from a crack tip and located on an inclined slip plane pile up against a grain boundary is performed and both the angular dependence of crack tip opening displacement and the change of CTOD during the crack growth through a crystal grain are examined. It is suggested from the results that the fatigue crack most easily propagates through a crystal grain and its boundary when an angle between the crack front and the slip plane is between 70 and 80 degress.
Furthermore, the analysis of the screw dislocations piled up against a thin-surface-layr is performed as one of the application of the dislocation dynamics and calculated the stress field generated in the layr by both the pile-up of dislocations and applied stress. The effects of the thickness of the layr, misfit of shear moduli, grain size and friction stress on the magnitude of the stress field in the thin-layr can be evaluated.

Report

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

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Kenji SAITO: "Analysis of Interaction Fields between Inclusion and Crack by means of Dislocation Dynamics" THEORETICAL AND APPLIED MECHANICS. 44. 145-154 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tatsuro MORITA: "Analysis of Stress Field Generated in Thin-Layer by Pile-up of Screw Dislocations" THEORETICAL AND APPLIED MECHANICS. 44. 137-144 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tatsuro MORITA: "Simulation of Fatigue Crack Growth by Dislocation Dynamics" THEORETICAL AND APPLIED MECHANICS. 45.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Kenji SAITO,Shigetoshi ARAKI,and Akihiro KARIYA: "Analysis of Interaction Fields between Inclusion and Crack by means of Dislocation Dynamics" THEORETICAL AND APPLIED MECHANICS. Vol.44. 145-154 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tatsuro MORITA,Kenji SAITO,and Masao SHIMIZU: "Analysis of Stress Field Generated in Thin-Layr by Pile-up of Screw Dislocations" THEORETICAL AND APPLIED MECHANICS. Vol.44. 137-144 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Tatsuro MORITA and Kenji SAITO: "Simulation of Fatigue Crack Growth by Dislocation Dynamics." THEORETICAL AND APPLIED MECHANICS. Vol.45. (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Kenji SAITO: "Analysis of Interaction Fields between Inclusion and Crack by means of Dislocation Dynamics" THEORETICAL AND APPLIED MECHANICS. 44. 145-154 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Tatsuro MORITA: "Analysis of Stress Fields Generated in Thin-Layer by Pile-up of Screw Dislocations" THEORETICAL AND APPLIED MECHANICS. 44. 137-144 (1995)

    • Related Report
      1995 Annual Research Report

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

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