• Title/Summary/Keyword: Non-isothermal Forming Analysis

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Finite Element Analysis and Experimental Investigation of Non-isothermal Forming Processes for Aluminum-Alloy Sheet Metals (Part2:Analysis) (알루미늄 합금박판 비등온 성형공정의 유한요소 해석 및 실험적 연구 (제2부:해석))

  • 김성민;구본영;금영탁;김종호
    • Transactions of Materials Processing
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    • v.8 no.3
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    • pp.252-261
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    • 1999
  • The 3-dimensional finite element program is developed to analyze the non-isothermal forming processes of aluminum-alloy sheet metals. Bishop's method is introduced to solve the heat balance and force equilibrium equations. Also, Barlat's non-quadratic anisotropic yield function depicts the planar anisotropy of the aluminum-alloy sheet. To find an appropriate constitutive equation, four different forms are reviewed. For the verification of the reliability of the developed program, the computational try-outs of the non-isothermal cylindrical cupping processes of AL5052-H32 and Al1050-H16 are carried out. As results, the constitutive equation relating to strain and strain-rate, in which the constants are represented by the 5th-degree polynomials of temperature, is in good agreement with measurement. The computational try-outs can predict optimal forming conditions in non-isothermal forming processes.

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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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Finite Element Analysis of warm Circular Cup Deep Drawing Process of AZ31 Sheet (AZ31 판재의 온간 원형컵 딥드로잉 공정의 유한요소 해석)

  • Lee, M.H.;Kim, H.Y.;Kim, H.K.;Oh, S.I.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.230-233
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    • 2007
  • Due to their low density, high specific strength and electromagnetic interference shielding, magnesium alloy sheets are used increasingly more often in automotive, aerospace, and electronics industries. However, magnesium ally sheets should be usually formed at elevated temperature because of their poor formability at room temperature. For the use of magnesium alloy sheets for an industrial, their mechanical properties at elevated temperature and appropriate forming process conditions have to be developed. In this study, the warm deep drawing process of AZ31 sheets is studied numerically by non-isothermal simulation. The difference between the isothermal simulation results and the non-isothermal simulation results and the progress of warm forming are discussed.

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Prediction of the Forming Load of Non-Axisymmetric Isothermal Forging using Approximate Similarity Theory (근사 상사 이론을 이용한 비축대칭 등온 단조의 가공하중 예측)

  • 최철현
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.71-75
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    • 1999
  • An approximate similarity theory has been applied to predict the forming load of non-axisymmetric forging of aluminum alloys through model material tests. The approximate similarity theory is applicable when strain rate sensitivity geometrical size and die velocity of model materials are different from those of real materials. Actually the forming load of yoke which is an automobile part made of aluminum alloys(Al-6061) is predicted by using this approximate similarity theory. Firstly upset forging tests are have been carried out to determine the flow curves of three model materials and aluminum alloy(Al-6061) and a suitable model material is selected for model material test of Al-6061 And then and forging tests of aluminum yokes have been performed to verify the forming load predicted from the model material which has been selected from above upset forging tests, The forming loads of aluminum yoke forging predicted by this approximate similarity theory are in good agreement with the experimental results of Al-6061 and the results of finite element analysis using DEFORM-3D.

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Hot Stamping Simulations and Experiments for CTBA Tubular Beams (CTBA Tubular Beam의 열간 성형해석 및 실험)

  • Suh, C.H.;Kim, W.S.;Sung, J.H.;Park, J.K.;Kim, Y.S.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.24 no.1
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    • pp.13-19
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    • 2015
  • For an accurate analysis of hot stamping, a coupled simulation with different aspects of the process(i.e. mechanical, thermal, and phase transformation) is needed. However, coupled simulations are time consuming and costly. Therefore, the current study proposes a simplified method focused on the forming for the hot stamping simulation of a coupled torsion beam axle (CTBA) tubular beam. In this simplified method, non-isothermal conditions were assumed and only conduction was considered, since it represents the majority of the heat transfer during hot stamping. In addition, temperature and strain rate effects were also included. Moreover, an isothermal simulation was conducted and compared with a non-isothermal simulation. Finally, the simulations were verified by experiments. In conclusion, the proposed method is shown to be effective for the development of tube-type parts, and it effectively predicts the deformation of the tubular beam during hot stamping.

The Effect of Preform Shape for Hot-forging Process of Aluminum-alloy (예비성형체형상이 알루미늄합금의 열간단조공정에 미치는 영향)

  • Kwon, Y.M.;Lee, Y.S.;Song, J.I.;Lee, J.H.
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.106-110
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    • 2001
  • A effective and accurate method of hot-forging process is essential to the design of optimized dies as well as workpiece of intial shape. the former is achieved by a proper forging sequence with invokes serious problem like excessive load and die wear, die failure, underfilling and lap defects. the latter is achieved by a proper preform design of case I, case II, case III. metal forming processes of aluminum-alloy forged at an effective strain and temperature are analyzed by the finite element method. the non-isothermal analysis have been compared with optimized in terms of preform shape.

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Finite Element Simulation of a Hot Aluminum Roll Forging Process and its Experimental Verification (열간 알루미늄 롤단조 공정의 유한요소해석과 실험적 검증)

  • Eom, J.G.;Li, Q.S.;Lee, M.C.;Joun, M.S.;Jung, S.J.;Park, G.H.;Gwak, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.437-440
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    • 2009
  • In this paper, an aluminum ring forging process of manufacturing an optimized perform for a hot forging process is simulated using AFDEX 3D, a general-purpose metal forming simulator based on rigid-thermoviscoplastic finite element method. Non-isothermal analysis is carried out and the predictions are compared with the experiments in terms of dimensional accuracy. It was shown that the predictions are in good agreement with the experiments.

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Finite Element Analysis of Rubber Extrusion Forming Process (고무 압출성형 공정에 대한 유한요소 해석)

  • Ha, Yeon-Sik;Cho, Jin-Rae;Kim, Tae-Ho;Kim, Jun-Hyoung
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.762-767
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    • 2007
  • As a macromolecule material, melted rubber flow shows characteristics of shear thinning fluid. The dynamic viscosity of this rubber fluid is influenced by temperature and shear strain rate. In this study, the numerical simulation of rubber extrusion forming process has been performed using commercial CFD code, Polyflow. Power-law model considering the effect of shear rate is used for the computer simulation of this non-Newyonian flow. Also Non-isothermal behavior is considered as Arrhenius-law model. Distributions of velocity and temperature are predicted through the simulation.

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