2005 Fiscal Year Final Research Report Summary
Constitutive models of plasticity for anisotropic sheet metals for cold/warm forming and their forming simulation applications
| Project/Area Number |
15360057
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
YOSHIDA Fusahito Hiroshima University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (50016797)
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| Co-Investigator(Kenkyū-buntansha) |
HINO Ryutaro Hiroshima University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (10283160)
UEMORI Takeshi Hiroshima University, Graduate School of Engineering, Research Associte, 大学院・工学研究科, 助手 (70335701)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Sheet metal forming / Plasticity / Constitutive model / Yield surface / Steel sheet / Magnesium alloy sheet / Aluminum alloy sheet |
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| Research Abstract |
This work deals with the constitutive modeling of plasticity and its application to sheet metal forming simulations. The summary of the research results is as follows :
[1] Constitutive modeling
(1) A constitutive model of large-strain cyclic plasticity, which properly describes the Bauschinger effect and cyclic hardening characteristics, as well as the anisotropy of sheet metals, Yoshida-Uemori model, has been proposed. This model has been verified by comparing the simulated results with the corresponding experimental results for deformation behavior in cyclic plasticity and bi-axial stretching tests.
(2) A model to describe the yield-point phenomena of annealed steels has been proposed.
(3) The effects of temperature and strain rates on the visco-plastic behavior of an aluminum alloy (A5083) and a magnesium alloy (AZ31) sheets were experimentally investigated. Based on the experimental observations, constitutive models of visco-plasticity have been presented.
[2] Numerical simulations and process design for sheet metal forming
(1) The above Yoshida-Uemori model has been implemented to a commercial FE code of PAM-STAMP, and using this, FE simulations of a hat-type draw-bending and S-rail forming were performed. From the results, it was found that the predictions of sheet draw-in and springback by this his model are more accurate than those calculated by a conventional model of the isotropic hardening plasticity.
(2) A new algorithm for springback analysis taking account of the elastic deformations of dies has been proposed.
(3) A method of springback control by optimum drawbead setting has been presented.
(4) A criterion for fracture limits of sheet metals under stretch bending has been proposed.
(5) Formability of adhesively-bonded sheet metals has been investigated by performing experiments and numerical simulations.
(6) A new technology of incremental sheet-metal forming with local heating has been proposed.
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