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Material Modeling, Numerical Simulation and Optimum Process Design for Metal Forming

keywords_en.jpgElasto-plasticity, Material Modeling, Metal Forming, Optimization Problems in Metal Forming 

division_en.jpg Hiroshima University Division of Intelligent Manufacturing Engineering

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Co-researcher : Ryutaro HINO,Hiroshi HAMASAKI

Outline

Background

For development of new forming technologies for materials with high
performance but with difficulty in forming, such as high strength steel sheets,
magnesium alloys etc., (1) material testing to determine the mechanical
properties, (2) modeling of material behavior of elasto-plasticity for numerical
simulations, and (3) optimum process design are required.

Research Summary

Mechanical behaviors of sheet metal, such as cyclic plasticity, yield locus and
forming limit curve, are investigated by original testing equipments. Material
models, which can describe these mechanical behaviors correctly, are
developed and material parameters for the models are identified. The
developed material models are used for FE simulation of metal forming
process. Furthermore, optimization of metal forming process based on FE
simulation and numerical optimization technique, and development of
incremental sheet forming method with local heating are also carried out.

Result

Yoshida-Uemori kinematic hardening model (Y-U model), which can precisely
describe cyclic plasticity of metals, was proposed. FE simulation using Y-U
model is capable of predicting springback of high strength steel sheets in stamping process, which was difficult to predict with
conventional material model. In addition, springback and wrinkle of high strength steel sheet products are successfully
suppressed by optimizing stamping process based on FE simulation. It is also possible to design the optimum forming process
in consideration of variation in material properties or forming conditions.

For Application

Material testing, material parameters identification, prediction of defects such as springback, wrinkle and fracture in sheet
stamping, and optimization of metal forming process for metal forming industries, especially sheet stamping industries.

Competitive Advances

Y-U model is included in several FE commercial codes, such as PAM-STAMP, LS-DYNA, etc. A software for material parameter
identification of Y-U model, MatPara, is developed and commercially available.

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F. Yoshida & T. Uemori: International Journal of Plasticity, 18 (2002), 661-686.

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