• Title/Summary/Keyword: Plane Strain Drawing

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Study on the Influence of Die Corner Radius for Deep Drawing of Elliptical Product of Automobile (자동차용 타원형 디프 드로잉 제품의 다이 반경에 관한 연구)

  • 허영민;박동환;강성수
    • Transactions of Materials Processing
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    • v.11 no.8
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    • pp.668-675
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    • 2002
  • The circles deform into various shape during deformation, the major and minor axes of which indicate the direction of the major and minor principal strains. Likewise, the measured dimensions are used to determine the major and minor principal strain magnitudes. This circular grid technique of measuring strains can be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, of incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.

Strain Analysis in the Slipline Field for Strip Drawing (판재인발 슬립라인장의 변형해석)

  • 구인회
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.4
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    • pp.660-669
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    • 1989
  • The strain distribution in a wide strip drawn through a wedge-shaped die is obtained from the numerical integration of strain increments along the flow path of material points in the slipline field for a non-hardening material under the plane strain condition. It is shown that the strain in the surface layer increases with friction and that the strain at the mid-plane is a function of area reduction only. The redundant deformation factor, obtained from the average strain in a drawn strip, increases with friction. For the workability analysis of a strip drawing process, the strain states along with hydrostatic stresses are needed for the evaluation of a damage function based on the hole-growth mechanism of ductile fracture. The critical maximum of the damage function is assumed to be a material constant. As a result, mid-plane cracking is likely to occur in a process at a small reduction, with a large die angle, and in poor lubrication. Distortions of an initially transverse line are also calculated.

Press Formabilities of Aluminum Sheets for Autobody Application (차체용 알루미늄 판재의 프레스 성형성)

  • Kim, Y.S.;Kim, K.S.;Kwon, N.C.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.1
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    • pp.73-83
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    • 1994
  • Press formabilities of aluminum sheets for automobile body were investigated. Plane strain stretching test (called RIST-PSST), cupping test and U bending test were performed to assess the press formability of aluminum sheets respectively. The results showed that aluminum sheets are generally inferior to cold-rolled steel sheet of deep drawing quality (CSP3N) in press formability. The limiting punch height (LPH) and limiting plane strain (FLCo) of aluminum sheets are 50%-70% level compared to that of CSP3N. Moreover, the limiting drawing ratios(LDR) of aluminum sheets are ranged between 1.95 and 2.1. The poor press formability of aluminum sheets is responsible for low values of total elongation and plastic anisotropy parameter in tensile characteristic. The shape fixability of aluminum sheets evaluated in U bending test is very poor due to its low elastic modulus compared to CSP3N.

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The Effects of Volume Ratio and Shape on the Formation of Adiabatic Shear Band in WHA (텅스텐 중합금의 부피분율, 입자형상에 따른 단열전단밴드 형성 연구)

  • 이승우;송흥섭;문갑태
    • Transactions of Materials Processing
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    • v.11 no.8
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    • pp.682-690
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    • 2002
  • The formation of adiabatic shearband in tungsten heavy alloys(WHA) was studied in this investigation. Five prismatic specimens were loaded by high velocity impacts and treated as plane strain problems. To find out the effect of particle's volume ratio, specimens containing 81%, 93% and 97% volume percents of tungsten particles were used. Also the effects of particle's geometry and size on the formation of shearband were studied for 81% volume percent alloys by small size particle model, large size particle model and undulated particle models, and the results were discussed.be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, or incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.

An Analysis for Drawing of Strip by UBET with Rigid Elements (강체요소를 이용한 인발 공정의 상계요소 해석)

  • Choi, Il-Kuk;Choi, Young;Hur, Kwan-Do
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.598-603
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    • 2001
  • For metal forming analysis, upper-bound solution is practical method because the solution is overestimated. It is limited to determine stresses on tools by using upper-bound solution. In this study, new scheme to calculate stresses on tools based on upper bound solution is proposed. To verify the proposed scheme, plane strain drawing has been considered. The stresses on tools obtained by the proposed scheme are compared with results of rigid plastic FEM. And the stresses on tools have been determined by the proposed scheme in the forging within plane strain deformation.

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A study on the drawing characteristics of drawbead by F.F.M (유한요소법에 의한 드로오비드 인출특성 연구)

  • 신양호
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.04a
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    • pp.42-47
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    • 1997
  • In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method by varying the process variables such as friction coefficient, drawbead radius, and closing depth. Numerical analysis are carried out by 2-D elastic-plastic F.E.M. The results are compared with the existing experimental results about the drawing force, the die clamping force, and the strain distribution of upper and lower sheet faces

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A study on the drawing characteristics of circular drawbead by the Finite Element Method (유한요소법에 의한 원형드로오비드의 인출특성에 관한 연구)

  • 신양호
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.3
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    • pp.26-35
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    • 1997
  • In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method. Both the clamping load and the drawing load investigated by varying the process variables such as drawbead radius, closing depth and friction condition. The effective strain induced by the draw bead is also investigated. In order to verify the results, the computed results are compared with the existing experimental results. It has been found that both the clamping load and drawing loads are related with the geometry of the bead rather than the lubrication conditions.

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Advanced simulative tests for formability determination (스탬핑 성형성평가를 위한 2,3의 모사실험)

  • 김영석
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.6
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    • pp.9-22
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    • 1992
  • 본 글에서는 판재의 스탬핑 성형성 평가를 위해 소재 제조업체와 자동차업체에서 널리 사용되고 있는 2,3개의 대표적인 모사실험과 평면변형장출실험을 소개하고 각각의 특징들에 대하여 논하고자 한다. 1. 딥 드로잉실험(deep drawing test after swift). 2. 돔 장출실험(dome punch stretching test). 3. 평면변형인장실험(plane strain tension test). 4. 평면변형장출실험(plane strain punch stretching test)

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Sectonal Forming Analysis of Stamping Processes of Aluminum Alloy Sheet Metals (알루미늄 합금 박판 스탬핑 공정의 단면 성형 해석)

  • 이광병;이승열;금영탁
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.10a
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    • pp.38-47
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    • 1996
  • Sectional analysis program for plane strain or axisymmetric geometry of aluminum alloy sheet metals was developed. For modeling the anomalous behavior of aluminum alloy, Barlat's strain rate potential and Hill's 1990 non-quadratic yield theory arranged under the plane stress assumption were employed. 2-D rigid-viscoplastic FEM formulation based on the bending-augmented membrane theory was derived, solving simultaneously force equilibrium as well as non-penetration condition. Isotropic hardening law was also assumed for yielding behavior. To verify the validity and availability of the developed program, 2-D stretch/draw forming process for plane strain geometry and cylindrical cup deep drawing process for axisymmetric geometry were simulated.

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Plane-Strain Analysis of Auto-Body Panel Using the Rigid-Plastic Finite Element Method (강소성 유한요소법을 이용한 자동차 판넬 성형공정의 평면 변형해석)

  • 양동열;정완진;송인섭;전기찬;유동진;이정우
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.169-178
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    • 1991
  • A plane-strain finite element analysis of sheet metal forming is carried out by using the rigid-plastic FEM based on the membrane theory. The sheet material is assumed to possess normal anisotropy and to obey Hill's new yield criterion and its associated flow rule. A formulation of initial guess generation for the displacement field is derived by using the nonlinear elastic FEM. A method of contact treatment is proposed in which the skew boundary condition for arbitrarily shaped tools is successively used during iteration. In order to verify the validity of the developed method, plane-strain drawing with tools in analytic expression and with arbitrarily shaped tools is analyzed and compared with the published results. The comparison shows that the present method can be effectively used in the analysis of plane-strain sheet metal forming and thus provides the basis of approximate sectional analysis of panel-like sheet forming.