• Title/Summary/Keyword: Discrete Kirchhoff Shell Element : Sheet Forming Analysis : Contact Searching : Penalty Method : Hierarchical Structure

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Sheet Forming Anlysis by Using Hierarchical Contact Searching Method (계층적 접촉 탐색방법을 이용한 박판성형 공정해석)

  • 김일권;김용한
    • Transactions of Materials Processing
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    • v.9 no.3
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    • pp.274-283
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    • 2000
  • A dynamic explicit finite element code for simulating sheet forming processes has been developed. The code utilizes the discrete Kirchhoff shell element and contact force is treated by a conventional penalty method. In order to reduce the computational cost, a new and robust contact searching algorithm has been developed and implemented into the code. In the method, a hierarchical structure of tool segments is built for each tool at the initial stage of the analysis. hierarchical structure is built in a way to divide a box to 8 sub-boxes, 2 in each direction, until the lowest level of the hierarchical structure contains exactly one segment of the tool or empty. Then at each time step, contact is checked from the box to sub-boxes hierarchically for each node. Comparisons of computational results of various examples with the existing ones show the validity of the method.

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A Hierarchical Contact Searching Algorithm in Sheet Forming Analysis (박판성형공정해석에서의 계층적 접촉탐색 알고리즘 적용)

  • 김용환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.22-25
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    • 1999
  • A dynamic explicit finite element code for simulating sheet forming processes has been developed The code utilises the discrete Kirchhoff shell element and contact force is treated by a conventional penalty method. In order to reduce the computational cost a new and robust contact searching algorithm has been developed and implemented into the code. in the method a hierarchical structure of tool segments called a tree structure is built for each tool at the initial stage of the analysis Tree is built in a way to divide a trunk to 8 sub-trunk 2 in each direction until the lowest level of the tree(leaf) contains exactly one segment of the tool. In order to have a well-balanced tree each box on each sub level contains one eighth of the segments. Then at each time step contact line from a node comes out of the surface of the tool. Simulation of various sheet forming processes were performed to verify the validity of the developed code with main focus on he usefulness of the developed contact searching algorithm.

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