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Construction and Application of Wrinkling Limit Diagram (WLD)

Research Project

Project/Area Number 05555034
Research Category

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

Allocation TypeSingle-year Grants
Research Field Materials/Mechanics of materials
Research InstitutionKobe University

Principal Investigator

TOMITA Yoshihiro  Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (10031147)

Co-Investigator(Kenkyū-buntansha) NAKAMACHI Eiji  Osaka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60099893)
ADACHI Taiji  Kobe University, Faculty of Engineering, Research Associate, 工学部, 助手 (40243323)
MIMURA Kouji  Kobe University, Faculty of Engineering, Research Associate, 工学部, 助手 (70181972)
TADA Yukio  Kobe University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (70135812)
Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1993: ¥4,200,000 (Direct Cost: ¥4,200,000)
KeywordsSheet Metal Forming / Wrinkle Formation / Forming Limit / Wrinkling Limit Diagram (WLD) / Plastic Instability / Bifurcation / Computational Simulation / Anisotropy
Research Abstract

This research aims at to provide a computational tool for predicting the onset of wrinkles during the general forming processes used on thin-walled bodies. It is assumed that the bodies are thin enough to deform along a completely lubricated tool surface to satisfy the membrane stress condition until wrinkling. A corner type constitutive equation with a general anisotropic quadratic yield function for a thin-walled bodies is developed. The onset of wrinkles is assumed to be a bifurcation from the membrane type of deformation to the bending type of deformation. Hill's general theory of bifurcation and uniqueness is employed in conjunction with Donnell-Mushtari-Vlasov's thin shell theory and Naghdi's linear thin shell theory to formulate the problem.
An analytical solutions have been presented to the condition of the onset of wrinkling for the curved sheets with different thickness under the variety of stress conditions. The results are summarized as the wrinkling limit diagram (WLD) which present the combinations of the critical principal stresses for the assumed mode of wrinkles. This can be used to predict the onset of wrinkling during the sheet metal forming processes as is done for the prediction of the forming limit of sheet metals with Forming Limit Diagram (FLD) by using the local stresses estimated by the computational simulations.
For the complicated problems, direct numerical searching strategies of the critical stress conditions for the onset of wrinkling have been employed. This can be also introduced to the computational simulation of shin sheet metal forming processes. Furthermore, to clarify the growth rate of wrinkles three dimensional analysis with isoparametric shell element and the same constitutive equation has been done. Parametric studies have been performed to investigate the effect of material characteristics, boundary condition and shape of the sheet metal on the wrinkling processes.

Report

(3 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report

Research Products

(26 results)

All Other

All Publications

  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(和文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(欧文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(欧文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(欧文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(欧文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(欧文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications] 「研究成果報告書概要(欧文)」より

    • Related Report
      1994 Final Research Report Summary
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1994 Annual Research Report
  • [Publications]

    • Related Report
      1993 Annual Research Report
  • [Publications]

    • Related Report
      1993 Annual Research Report
  • [Publications]

    • Related Report
      1993 Annual Research Report
  • [Publications]

    • Related Report
      1993 Annual Research Report
  • [Publications]

    • Related Report
      1993 Annual Research Report
  • [Publications]

    • Related Report
      1993 Annual Research Report

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

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