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材料の分岐変形に関する弾塑性変形解析と微小疲労き裂進展挙動解明への応用

Research Project

Project/Area Number 04F04078
Research Category

Grant-in-Aid for JSPS Fellows

Allocation TypeSingle-year Grants
Section外国
Research Field Materials/Mechanics of materials
Research InstitutionKyushu University

Principal Investigator

村上 敬宜  九州大学, 大学院・工学研究院, 教授

Co-Investigator(Kenkyū-buntansha) KHOJASTEHPOUR Mehdi  九州大学, 大学院・工学研究院, 外国人特別研究員
KHOJASTEHPOUR M  九州大学, 大学院・工学研究院, 外国人特別研究員
Project Period (FY) 2004 – 2005
Project Status Completed (Fiscal Year 2005)
Budget Amount *help
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
KeywordsBifurcation and Instability / Elastoplasticity / Constitutive Behavior / Elastoplastic Materials / Subloading Surface Model / Crack tip Plasticity / Dislocation Mechanics / Mixed Mode Fracture / Shear Band / Bifurcation
Research Abstract

Elastoplastic analysis of bifurcation and application to fatigue threshold analysis of small cracks
Bifurcation :
Analytical solutions are presented for the localized and diffuse bifurcations of an incompressible circular cylinder subjected to axisymmetric loading, whose constitutive behavior is described by adopting the tangential-subloading surface model falling within the framework of tangential plasticity. The analysis includes the conditions for shear band formation, shear band inclination, diffuse buckling formation, and the long and short wavelength limits of diffuse buckling modes in relation to material properties and stress. It becomes well-informed that the normal-yield ratio describing the degree of approach to the normal-yield state, the tangential-plastic strain rate due to the tangential-stress rate effect and the kinematic hardening variable influence the onset of localized and diffuse bifurcations.
Fatigue and Fracture :
The characterization of the elastoplastic zone at the tip of a blunt crack under mixed mode loading was discussed. The deformed zone appearing at the crack front is described by presenting a criterion based on the subloading surface concept falling within the framework of unconventional plasticity. It is revealed that the mixed mode crack propagates along the minimum value of the elastoplastic region.
A study was conducted to clarify the behavior of a dislocation located on the inclined plane near a finite crack. Equations were presented for the forces based on the interactions between a finite crack and the dislocations near the crack tip. The influences of crack length on the forces applied to a dislocation were investigated using the extended equations.

Report

(2 results)
  • 2005 Annual Research Report
  • 2004 Annual Research Report
  • Research Products

    (11 results)

All 2006 2005 2004

All Journal Article (11 results)

  • [Journal Article] Antisymmetric bifurcation in an elastoplastic cylinder with tangential plasticity2006

    • Author(s)
      Khojastehpour, M., Murakami.Y, Hashiguchi.K.
    • Journal Title

      Mechanics of Materials 38(In press)

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Antisymmetric bifurcation in elastoplastic cylinders under uniaxial compression2005

    • Author(s)
      Khojastehpour, M., Murakami.Y, Hashiguchi.K.
    • Journal Title

      Journal of Applied Mechanics JSCE 8

      Pages: 361-366

    • NAID

      130004258301

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Elastoplastic zone and crack initiation in blunt-notched plates2005

    • Author(s)
      Khojastehpour, M., Murakami.Y, Hashiguchi.K.
    • Journal Title

      ICCES'05, Chennai, India, December 1-6 41

      Pages: 2274-2279

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Crack tip plasticity in edge-blunt-cracked plates2005

    • Author(s)
      Khojastehpour, M., Murakami.Y.
    • Journal Title

      McMat2005, Baton Rouge, Louisiana, USA, June 1-3 Paper No.464

      Pages: 1-6

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Plane strain dynamic bifurcation with tangential plasticity2005

    • Author(s)
      Khojastehpour, M.
    • Journal Title

      McMat2005, Baton Rouge, Louisiana, USA, June 1-3 Paper No.36

      Pages: 1-6

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Plane strain bifurcation with tangential plasticity2005

    • Author(s)
      Khojastehpour, M., Hashiguchi.K., Murakami.Y.
    • Journal Title

      Plasticity'05, Kauai, Hawaii, USA, January 3-8

      Pages: 268-270

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Axisymmetric bifurcations of metals tangential-subloading surface model2004

    • Author(s)
      Khojastehpour, M., Hashiguchi.K., Murakami, Y.
    • Journal Title

      Journal of Applied Mechanics, JSCE 7

      Pages: 527-534

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Axisymmetric bifurcation analysis in soils by the tangential-subloading surface model2004

    • Author(s)
      Khojastehpour, M., Hashiguchi, K.
    • Journal Title

      Journal of the Mechanics and Physics of solid 52

      Pages: 2235-2262

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Plane strain bifurcation analysis of solids by the tangential-subloading surface model2004

    • Author(s)
      Khojastehpour, M., Hashiguchi.K.
    • Journal Title

      International Journal of Solids and Structures 41

      Pages: 5541-5563

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Axisymmetric bifurcation analysis with tangential plasticity2004

    • Author(s)
      Khojastehpour, M., Hashiguchi.K., Murakami.Y.
    • Journal Title

      ICCES'04, Madeira, Portugal, July 26-29

      Pages: 800-805

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Localized bifurcation in soils with tangential plasticity2004

    • Author(s)
      Khojastehpour, M., Hashiguchi.K., Murakami.Y.
    • Journal Title

      The 39th Japan National Conference on Geotechnical Engineering, Niigata, Japan, July 6-9

      Pages: 1151-1152

    • NAID

      130004621795

    • Related Report
      2004 Annual Research Report

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Published: 2004-04-01   Modified: 2024-03-26  

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