• Title/Summary/Keyword: Non-isothermal Sheet Metal Forming

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A Finite Element Analysis of Non-Isothermal Sheet Metal Forming Process (비등온 박판 성형공정의 유한요소해석)

  • ;Wagoner, R. H.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1119-1128
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    • 1990
  • A numerical method for analyzing non-isothermal, rigid-viscoplastic deformation problems has been presented. As an application, a stretch forming of sheet metals, including temperature effect, has been analyzed by a three-dimensional finite element method. Bishop`s step-wise decoupled method is adopted to solve thermomechanical coupling between deformation and heat transfer. Using the method, the effect of temperature on strain distribution during stretch forming is investigated. By comparison of the non-isothermal results with isothermal analysis, the importance of including temperature effects in the analysis of metal forming problems is emphasized. The predicted results were in good agreement with the existing experimental measurements at the different punch temperatures and dome heights investigated. It is also found that any increase of the punch temperature appeared to postpone the strain localization process by lowering the peak strain in the critical punch-sheet contact region and by normalizing strain distribution within the specimen.

Development of Finite Element Program for Analyzing Springback Phenomena of Non-Isothermal Forming Processes for Aluminum Alloy Sheets (Part2 : Theory & Analysis) (알루미늄 합금박판 비등온 성형공정 스프링백 해석용 유한요소 프로그램 개발 (2부 : 이론 및 해석))

  • ;;R.H. Wagoner
    • Transactions of Materials Processing
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    • v.12 no.8
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    • pp.710-717
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    • 2003
  • The implicit, finite element analysis program for analyzing the springback in the warm forming process of aluminum alloy sheets was developed. For the description of planar anisotropy in warm forming temperatures, Barlat's yield function is employed, and the power law type constitutive equation is used in terms of working temperatures for the depiction of work hardening in high temperatures. Also, Jetture's 4-node shell elements are introduced for reflecting the mechanical behavior of aluminum alloy sheet and the non-steady heat balance equations are solved for considering heat gain and loss during the forming process. For the springback evaluation, Newton-Raphson iteration method is introduced for overcoming the geometric nonlinearlity problem. In order to verify the validity of the FEM program developed, the stretching bending and springback processes are simulated. Though springback analysis results are slightly bigger than experimental ones, they have the same trend of the decreasing springback as the forming temperature increases.

Development of Finite Element Program for Analyzing Springback Phenomena of Non-isothermal Forming Processes for Aluminum Alloy Sheets (Part II : Theory & Analysis) (알루미늄 합금박판 비등온 성형공정 스프링백 해석용 유한요소 프로그램 개발 (2부 : 이론 및 해석))

  • Keum Y. T.;Han B. Y.;Wagoner R.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.08a
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    • pp.13-20
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    • 2003
  • The implicit, finite element analysis program for analyzing the springback in the warm forming process of aluminum alloy sheets was developed. For the description of planar anisotropy in warm forming temperatures, Barlat's yield function is employed, and the power law type constitutive equation is used in terms of working temperatures fur the depiction of work hardening in high temperatures. Also, Jetture's 4-node shell elements are introduced for reflecting the mechanical behavior of aluminum alloy sheet and the non-steady heat balance equations are solved for considering heat gain and loss during the forming process. For the springback evaluation, Newton-Raphson iteration method is introduced for overcoming the geometric nonlinearlity problem. In order to verify the validity of the FEM program developed, the stretching bending and springback processes are simulated. Though springback analysis results are slightly bigger than experimental ones, they have the same trend of the decreasing springback as the forming temperature increases.

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