| Co-Investigator(Kenkyū-buntansha) |
YOKOUCHI Yasuto University of Electro-Communications, Faculty of Electro-Communications, Associa, 電気通信学部, 助教授 (50013214)
MAKINOUCHI Akitake The RIKEN Institute, Research Scientist, 研究員 (80087460)
TOMITA Yoshihiro Kobe University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (10031147)
GOTOH Manabu Gifu University, Faculty of Engineering, Professor, 工学部, 教授 (60023165)
KAWAI Ken'ichi Yokohama National University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60114972)
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| Research Abstract |
As the first benchmark test, "axisymmetric, plane strain and plane stress unusual tension of a bar with both ends fixed" was examined on the FEM codes owned by every participant to this project; mesh division and element type, constitutive equations, and an incremental value of deformation per one step were unified for all the FEM codes. As a result, plane stress tension was found to be sensitive to the above calculation conditions and thus as the second benchmark test, "unusual tension of sheet metal (plane stress) with both ends fixed" was conducted more precisely. In the course of the first and second benchmark tests, the FEM codes of the participants were checked and standardized; consequently, a good accord with each other's calculated results was attained. As the third benchmark test, "simple shear of sheet metal (plane stress) and block (plane strain) with both ends fixed" was conducted in order to check the effects of rigid body rotation on the calculated values of stress. Furt
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hermore, as the forth benchmark test "ring compression", a typical test which includes frictional boundary conditions, was carried out, and as the fifth benchmark test "plane strain bending of plate" was done in order to clarify causes of the unbalance of moment of force occurring as large deformation proceeds. The crude calculated results obtained through the first to fifth benchmark tests were tabulated and collected as a standardized database for checking the accuracy of numerical analyses of metal-forming processes. Further investigation has been hoped for the forth and fifth benchmark tests.
As basic research on plastic deformation analyses of metal-forming processes, a serial commentary on plastic constitutive equations was published in the Journal of Japan Society for Technology of Plasticity, being related to sbrain-rate dependency, temperature dependency, anisotropy, and bifurcation of deformation. Several subjects known to cause problems in elastic-plastic and rigid-plastic FEM analyses, such as mesh geometry, mesh division, number of integral points, incremental values of deformation, and methods of smoothing the material deformation around tool-edge, were also examined. Causes of the unbalance of moment of force occurring in bending problems were investigated using a single mesh model of a 2-D linear triangle element. Less
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