1987 Fiscal Year Final Research Report Summary
Development of Three Dimensional Boundary Element Solidification Analysis with Aid of CAD
| Project/Area Number |
61550505
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属加工(含鋳造)
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| Research Institution | Department of Metallurgy, Faculty of Engineering, University of Tokyo |
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Principal Investigator |
AIZAWA Tatsuhiko Associate Professor, 工学部, 助教授 (10134660)
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| Project Period (FY) |
1986 – 1987
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| Keywords | CAD / Three Dimensional BEM / Solidification Analysis / Geometric Model / High-Speed Computation / Supercomputer / New Formulation / Symbolic Manipulation / Computational Model / Quad-Tree / 修正4分木モデル |
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| Research Abstract |
Through this project, a part of work station for solidification analysis is completed, and three dimensional boundary element program code has been developed for heat transfer problem with latent heat and phase change taken into account. Since complicated geometries must be treated in the practical casting design analysis, various discussions and considerations are made to improve efficiency and reliability of the present casting analysis.
We will point out the key technologies which were obtained through the present study:
(1) Use of characteristics in fundamental solution enables us to compress the fully-populated coefficient matrix which appears in the conventional boundary element analysis,
(2) Since optimum time increment can be employed in the present approach, we can save the number of time steps, and solve the simultaneous equations efficiently by the iterative method,
(3) Instead of the manual handling of the explicit forms including the fundamental solutions or their derivatives in implementation of boundary element analysis, symbolic manipulation aids us to make boundary element formulations,
(4) To realize the effective casting design analysis with solidification taken into account, geometric model and computational model for meshing are both considered; quad-tree and modified quad-tree model is proposed to deal with the shape design and the complete automeshing in the two dimensional heat transfer problems. Since set operation or boolean operations can be defined on the basis of the above quad-tree/modified quad-tree model, change of figures or mechings and construction of complicated geometry/meshing from simple models can be performed to support computer aided engineering in practical casting design,
(5) Automatic generation of tetrahedral meshing elements is proposed, and its program is constructed at the first trial for the future three dimensional casting design.
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