Researchers, Developers and Staffs
Takayuki HAMA Takayuki HAMA


Research Themes

Development of accurate simulation software for sheet metal forming processes

Research Subjects and Results

In order to carry out a precise simulation of sheet metal forming processes, the sheet forming simulation software STAMP3D has been developed in order to be able to use the advanced features of the VCAD model for the description of the stamping tools. In this study, new techniques for the sheet metal forming simulation using the Nagata patch [Nagata, Comput. Aided Geom. D, 22(2005), 327-347] have been developed. The Nagata patch enables the creation of tool models that are much more accurate than those of conventional polyhedral representations. The proposed techniques allow an improved description of the contact between the sheet nodes and the tool surfaces. The simulation results of several sheet forming processes are rather independent of the tool mesh when using the Nagata patch model, demonstrating the efficiency and reliability of the proposed techniques. Furthermore, to verify experimentally the simulation using the Nagata patch tool model, simulations of a draw-bending process using high-strength steel of 780 MPa grade were carried out and the results were compared with the experimental results. When a conventional tool modelling that directly uses polyhedral surfaces was employed, there were cases where the amount of springback obtained by the simulation was much smaller than the experimental result. This discrepancy was owing to large geometrical errors on the tool surfaces. On the other hand, when the Nagata patch tool model was used, the simulation results were in good agreement with the experimental results regardless of the simulation conditions. This agreement was due to the accurate geometries of the tool surfaces achieved by the Nagata patch, confirming the validity of the proposed technique. Moreover, a simulation of a three-dimensional hat channel forming process was carried out using STAMP3D, and twist phenomena occurring during springback was investigated.

VCAD Public Software

V-Stamp

Software Block Page


Selected Publications

【Papers】
Banu, M., Takamura, M., Hama, T., Naidim, O., Teodosiu, C. and Makinouchi, A.
「Simulation of springback and wrinkling in stamping of a dual-phase steel rail-shaped part,」
Journal of Materials Processing Technology, 173-2, 178-184, 2006

Hama, T., Ohkubo, T., Kurisu, K, Fujimoto, H. and Takuda, H.
Formability of tube hydroforming under various loading paths
Journal of Materials Processing Technology, 177, 676-679, 2006.

Hama, T., Hatakeyama, T., Asakawa, M., Amino, H., Makinouchi, A., Fujimoto, H. and Takuda, H.
Finite-element simulation of the elliptical cup deep drawing process by sheet hydroforming
Finite Elements in Analysis and Design, 43, 234-246, 2007.

Hama, T., Takamura, M., Teodosiu, C., Makinouchi, A. and Takuda, H.
Effect of tool modeling accuracy on sheet metal forming simulation
Key Engineering Materials, 340-341, 743-748, 2007.

Hama, T., Nagata, T., Teodosiu, C., Makinouchi, A. and Takuda, H.
Finite-element simulation of springback in sheet metal forming using local interpolation for tool surfaces
International Journal of Mechanical Sciences, 50, 175-192, 2008.

Hama, T., Takamura, M., Makinouchi, A., Teodosiu, C., and Takuda H.
Formulation of contact problems in sheet metal forming simulation using local interpolation for tool surfaces
Journal of Computational Science and Technology, 2-1, 68-80, 2008.

Banu, M., Hama, T., Alves, J.L., and Naidim, O.
Numerical prediction of the stress fields in a bending unbending forming stage using STAMP3D and DD3IMP
Steel Research International 79, Special Edition, vol. 1, 186-193, 2008.

Hama, T., Iguchi, K., Hishida, H., and Takuda, H.
Roll forming simulations of a steel sheet using various finite element method codes
Steel Research International 79, Special Edition, vol. 2, 587-594, 2008.

Hama, T., Takamura, M., Makinouchi, A., Teodosiu, C. and Takuda, H.
Effect of tool modeling accuracy on square cup deep-drawing simulation
Materials Transactions, 49-2, 278-283, 2008.

Takamura, M., Sakata, M., Fukui, A., Hama, T., Miyoshi, Y., Sunaga, H., Makinouchi, A., and Asakawa, M.
Investigation of twist in curved hat channel products by elastic-plastic finite element analysis
International Journal of Material Forming, 3 Suppl. 1, 131-134, 2010.

Hama, T., Isogai, E., Yoshida, T., and Takuda, H.
Experimental verification of springback simulation using local interpolation for tool surfaces
Steel Research International, 81-9, Special Edition, 753-756, 2010.

Takamura, M., Fukui, A., Hama, T., Miyoshi, Y., Sakata, M., Sunaga, H., Makinouchi, A., Asakawa, M.
Twisting in Curved Hat Channel Products Made of High Strength Steel Sheet
Steel Research International, 81-9, Special Edition, 821-824, 2010.

Hama, T., and Takuda, H.
Crystal-Plasticity Finite-Element Analysis of Inelastic Behavior During Unloading in a Magnesium Alloy Sheet
International Journal of Plasticity, 2010.

Selected Publications Page