• Title/Summary/Keyword: Drawbead Restraining Force

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Development of Drawbead Expert Models for Finite Element Analysis of Sheet Metal Forming Processes(Part 2:Modeling) (박판성형공정의 유한요소해석을 위한 드로우비드 전문모델 개발(2부: 모델링))

  • Keum, Yeong-Tak;Lee, Jae-U
    • Transactions of Materials Processing
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    • v.7 no.1
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    • pp.12-22
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    • 1998
  • An expert drawbead model is developed for the finite element analysis of stamping processes. The expert model calculates drawbead restraining forces and bead-exit thinnings with the forming condi-tions and drawbead size. The drawbead restraining forces and bead-exit thinnings of a circular draw-bead and stepped drawbead are computed by mathematical models and corrected by the multiple lin-ear regression method based on experimental measurements. The squared drawbead preventing the sheet from drawing-in inside die cavity is assumed to have a very huge drawbead restraining force and no pre-strain just after drawbead. The combined beads are considered as a combination of basic draw-beads such as circular a drawbead stepped drawbead and squared drawbead so that the drawbead restraining forces and bead-exit thinnigs are basically sum of those of basic drawbeads.

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Study on the Drawbead Expert Models (드로우비드 전문모델에 관한 연구)

  • 김준환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.04a
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    • pp.26-29
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    • 2000
  • drawbead expert models are developed for calculating drawbead restraining force and drawbead-exit thinnings which are boundary conditions in FEM stamping simulation employing the linear multiple regression method by which the deviation of drawing characteristics between drawing test and mathematical model is minimized. In order to show the efficiency and accuracy of an expert drawbead model a finite element simulation of auto-body panel stamping is carried out. The finite element simulation shows that the expert drawbead model provides the accurate solution guarantees the stable convergence and the merit in the computation time.

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Prediction and Evaluation of Drawbead Restraining Force with Finite Element Analysis (유한요소해석을 통한 드로우비드 저항력의 예측 및 평가)

  • Bae G. H.;Song J. H.;Kim S. H.;Kim D. J.;Huh H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.87-90
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    • 2005
  • The drawbead is used to control the material flow into the die and increase the forming quality during the binder wrap process and the stamping process in the sheet metal forming. Drawbead restraining force (DBRF) is controlled by geometrical parameters and influenced by process parameters such as friction coefficient and blank thickness. In order to inspect the effect of process parameters, parameter studies are performed with the variation of parameters using finite element model of drawbead which is utilized reliably for the calculation of the drawbead restraining force. Drawbead analysis is carried out with 2-D plane-strain element and 3-D shell element. After the verification of the accuracy of the drawbead model with 3-D shell element, it is utilized to the prediction and the investigation of the effect of process parameters. The result of parameter studies can be utilized to the die design in the tryout stage.

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An Experimental Study on the Restraining Characteristics through Square Drawbead (사각형 드로오비드 인출 특성에 관한 실험적 연구)

  • 박원배;김창만;전기찬;서대교
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.03a
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    • pp.170-177
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    • 1995
  • The restraining characteristics for the single square drawbead are discussed. The drawbead restraining forces adn maximum strains by the various drawing angles are measured experimentally. During this procedure , the drawing angles are varied from 0$^{\circ}C$ to 60$^{\circ}C$. Also, the wide range of experimental data of the drawing forces and maximum strains for the various drawbead dimensions, dimensions, clearances and blank holding forces are preseted.

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Restraining Characteristics for Single Circular and Round Drawbead (단일원형비드 및 환저비드의 인출 특성에 관한 연구)

  • 김창만;임영석;이항수;전기찬;서대교
    • Transactions of Materials Processing
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    • v.3 no.4
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    • pp.454-467
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    • 1994
  • The drawbead restraining forces for the various radius of drawbead and die corner are analyzed by the belt theory, and they are compared with the experimental results. During this procedure, the drawing angles are also varied from $0^{\circ}$ to $60^{\circ}$, and the near part of the drawed die corner are divided into fur steps for the theoretical analysis. The stress distributions through the sheet thickness for these steps are also suggested theoretically. The wide range of experimental data of the drawing forces and strain distributions for the various dimension and blank holding forces are presented. It is concluded that the theoretical assumption for the restraining force analysis is very useful from the comparison with the experimental results.

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Study on the Measurement of Restraining and Opening Forces in Drawbeads (드로우비드 상압력과 인출력 측정에 관한 연구)

  • Moon, S.J.;Keum, Y.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.203-206
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    • 2006
  • The drawbeads, which is used for controlling the flow of the sheet by imposing the tension and for preventing the springback in the sheet metal forming process, affects a lot the formability because of the differences in the restraint and opening forces according to the drawbead shapes and dimensions. In this study, the experimental device enabling to measure the drawbead restraining forces and the drawbead opening forces associated with various drawbead shapes and dimensions and their theoretical evaluation are introduced and verified through the experimental measurement of those of a circular drawbead.

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Design of Drawbeads for Advanced High Strength Steel Sheet Forming (초고강도 강판 성형용 드로비드 설계)

  • Kim, B.G.;Jeong, J.Y.;Kim, D.J.;Kim, G.S.;Keum, Y.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.420-423
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    • 2009
  • In this study, the guideline for designing the drawbeads used in the stamping dies for advanced high strength steel (AHSS) sheets is investigated. In the drawbead drawing test, the drawbead forces for verifying the equivalent drawbead model(EDM) and the sheet strains for finding marginal strains from $FLC_0$ are measured. In the finite element analysis (FEA), the bending allowance, R/t, is obtained. Based on the forming and bending allowances obtained, the design guideline of the drawbead for determining height and width, which depends on the restraining force and the forming allowance, is prepared by using EDM.

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Application of Drawbead Expert Model to Finite Element Analysis of Forming Process for Auto-Body Panel (차체패널 성형공정 유한요소해석에 드로우비드 전문모델의 적용)

  • 금영탁;김준환
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.3
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    • pp.119-129
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    • 2000
  • In order to show the efficiency and accuracy of an expert drawbead model, finite element simulations of auto-body panel stampings are carried out. For numerical modeling of the drawbead of a panel die, the drawbead restraining force and bead-exit thinning calculated by the expert model are imposed to a node nearest to the drawbead position as a boundary condition, Finite element simulations show that the expert model provides the accurate solution, guarantees the stable convergence, and has the merit in the computation time.

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Development of Drawbead Expert Models for Finite Element Analysis of Sheet Metal Forming Processes (Part1:Experiment) (박판성형공정의 유한요소해석을 위한 드로우비드 전문모델 개발(1부: 실험))

  • Lee, Jae-U;Keum, Yeong-Tak
    • Transactions of Materials Processing
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    • v.7 no.1
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    • pp.3-11
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    • 1998
  • During the forming process of sheet metals, the drawbead in the die face controls a restraining force so that the sheet flows into the die cavity with tension. In order to investigate a drawgbead restraining force and a pre-strain just after drawbeads which are essential in the finite element analysis of form-ing processes, the friction test and drawing test are employed. The experiments performed with a cir-cular bead stepped bead double circular bead and circular-and-stepped bead in the various forming conditions and bead sizes show that the restraining force varies linearly with the blank holding force. bead radius blank thickness and friction but the pre-strain nonlinearly does with them.

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The Influence of the Number of Drawbead on Blank Forming Analysis (블랭크 성형해석시 드로우비드 개수가 미치는 영향에 관한 연구)

  • 정동원;이상제
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.2
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    • pp.193-200
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    • 2000
  • In the sheet metal forming process, the drawbead is used to control the flow of material during the forming process. The drawbead provides proper restraining force to the material and prevents defects such as wrinkling or breakage. For these reasons, many studies for designing the effective drawbead have been conducted. In this paper, the influence of the number of drawbead during the blank forming process will be introduced. For the analysis, the numerical method called the static-explicit finite element method was used. The finite element analysis code for this method has been developed and applied to the drawbead process problems. It is expected that this static-explicit finite element method could overcome heavy computation time and convergence problem due to the increase of drawbeads.

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