• Title/Summary/Keyword: Remeshing criteria

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A Remeshing Criterion for Large Deformation Finite Element Analysis (대변형 유한요소해석에서 요소망의 재구성을 위한 기준)

  • Cho, Hae-Gyu;Chae, Soo-Won;Park, Jong-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.78-87
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    • 1996
  • In this paper, a remeshing criterion has been suggested in order to order to automate the remeshing decision during finite element analysis of metal forming. In order to use for the remeshing decision, two of remeshing criteria have been investigated. One is the use of error estimates based on errors in stresses and strain rate of the finite element solution and the other is the use of geometric characterisreics of distorted elements. As a result, the strain rate error estimate in power norm based on the former is found to give more valuable information about remeshing decision than the ones based on the latter. Examples are given to demon- strate the usefulness of the suggested eroor estimate as a remeshing criterion.

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Development of Algorithm for Two Dimensional Automatic Mesh Generation and Remeshing Technique Using Bubble Packing Method (II) - Nonlinear Analysis - (버블패킹방법을 이용한 2차원 자동격자 생성 및 재구성 알고리듬 개발 (II) -비선형 해석-)

  • Jeong, Sun-Wan;Kim, Seung-Jo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.12
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    • pp.1926-1932
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    • 2001
  • In this second part of the paper, the automatic mesh generation and remeshing algorithm using bubble packing method is applied to the nonlinear problem. The remeshing/refinement procedure is necessary in the large deformation process especially because the mesh distortion deteriorates the convergence and accuracy. To perform the nonliear analysis, the transfer of state variables such as displacement and strain is added to the algorithm of Part 1. The equilibrium equation based on total Lagrangian formulation and elasto-viscoplastic model is used. For the numerical experiment, the upsetting process including the contact constraint condition is analyzed by two refinement criteria. And from the result, it is addressed that the present algorithm can generate the refined meshes easily at the largely deformed area with high error.

Automated Mesh Generation For Finite Element Analysis In Metal Forming (소성 가공의 유한 요소 해석을 위한 자동 요소망 생성)

  • 이상훈;오수익
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.10a
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    • pp.17-23
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    • 1997
  • In the two-dimensional Finite Element Method for forming simulation, mesh generation and remeshing process are very significant. In this paper, using the modified splitting mesh generation algorithm, we can overcome the limitation of existing techniques and acquire mesh, which has optimal mesh density. A modified splitting algorithm for automatically generating quadrilateral mesh within a complex domain is described. Unnecessary meshing process for density representation is removed. Especially, during the mesh generation with high gradient density like as shear band representation, the modified mesh density scheme, which will generate quadrilateral mesh with the minimized error, which takes effect on FEM solver, is introduced.

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A Study on the Thermo-elasto-plastic Analysis of Upset Forming (전기 업셋팅 가공시의 열탄소성 해석에 관한 연구)

  • 왕지석;박태인
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.4
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    • pp.69-76
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    • 1994
  • Thermal elasto-plastic analysis of axi-symmetric body by the finite element method is presented in this paper for analyzing the process of upset forming of circular section extruded bar. The example of calculation for upset forming of Nimonic extruded bar is also presented. It is shown that remeshing of quadrilateral finite element is necessary because the very highly distorted element by plastic deformation disturbs the calculation. Calculated values for nodal points in new mesh are obtained from nodal points of old mesh by linear interpolation method. The experimental results are compared with calculated values. The appearance of upsetupset forming obtained by experimental method is very similar to that obtained by calculations. So, it is proved that the thermal elasto-plastic analysis of axi-symmetric body by the finite element method is very useful for finding the optimum upsetting condition.

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A study on the micro-formability of $Zr_{62}Cu_{17}Ni_{13}Al_8$ Bulk Metallic Glasses using micro-forging and Finite Element Method applications (마이크로 단조를 이용한 Zr 계 벌크 비정질합금의 미세 성형성 평가와 유한요소해석 적용에 관한 연구)

  • Kang Sung-Gyu;Park Kyu-Yeol;Son Seon-Cheon;Lee Jong-Hon;Na Young-Sang
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.4 s.181
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    • pp.153-161
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    • 2006
  • Micro-forming is a suited technology to manufacture very small metallic parts(several $mm{\sim}{\mu}m$). Micro-forming of $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk metallic glass(BMG) as a candidate material for this developing process are feasible at a relatively low stress in the supercooled liquid state without any crystallization during hot deformation. In this study, micro- formability of a representative bulk metallic glass, $Zr_{62}Cu_{17}Ni_{13}Al_8$. was investigated for micro-forging of U-shape pattern. Micro-formability was estimated by comparing $R_f$ values ($=A_f/A_g$), where $A_g$ is cross-sectional area of U groove, and $A_f$ the filled area by material. Micro-forging process was simulated and analyzed by applying finite element method. FEM simulation results showed reasonable agreement with the experimental results when the material properties and simulation conditions such as top die speed, remeshing criteria and boundary conditions were tightly controlled. The micro-formability of $Zr_{62}Cu_{17}Ni_{13}Al_8$ was increased with increasing load and time in the temperature range of the supercooled liquid state. Also, FEM simulation using a commercial software, DEFORM was confirmed to be applicable for the optimization of micro-forming process.

A study on the micro-formability of $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk metallic glass using micro-forging and finite element method application (Zr 계 벌크비정질합금의 마이크로 단조를 이용한 미세 성형성 평가와 유한요소해석 적용에 관한 연구)

  • Kang S.G.;Na Y.S.;Park K.Y.;Son S.C.;Lee J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.589-592
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    • 2005
  • Micro-forming is a suited technology to manufacture very small metallic parts(several $mm{\sim}{\mu}m$). Micro-forming of $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk metallic glass(BMG) as a candidate material for this developing process are feasible at a relatively low stress in the supercooled liquid state without any crystallization during hot deformation. In this study, micro-formability of a representative bulk metallic glass, $Zr_{62}Cu_{17}Ni_{13}Al_8$, was investigated for micro-forging of U-shape pattern. Micro-formability was estimated by comparing $R_f$ values $(=A_f/A_g)$, where Ag is cross-sectional area of U groove, and $A_f$ the filled area by material. Microforging process was simulated and analyzed by applying finite element method. FEM simulation results should reasonable agreement with the experimental results when the material properties and simulation conditions such as top die speed, remeshing criteria and boundary conditions tightly controlled. The micro-formability of $Zr_{62}Cu_{17}Ni_{13}Al_8$ was increased with increasing load and time in the temperature range of the supercooled liquid state. Also, FEM Simulation using DEFORM was confirmed to be applicable for the micro-forming process simulation.

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