2004 Fiscal Year Final Research Report Summary
Multiscale Model of Transformation Induced Plasticity and its Application to Morphogenesis with High Functional
| Project/Area Number |
14350059
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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 | Kobe University |
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Principal Investigator |
TOMITA Yoshihiro Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (10031147)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAI Yoshikazu Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (90155656)
YASHIRO Kisaragi Kobe University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50311775)
ADACHI Taiji Kyoto University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40243323)
IWAMOTO Takeshi Hiroshima University, Faculty of Engineering, Research Associate, 工学部, 助手 (40274112)
HIGA Yoshikazu Osaka University, Faculty of Engineering, Research Associate, 工学部, 助手 (20335368)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Deformation Induced Transformation / Micromechanical Model / Mesomechanical Model / Homogenization Method / Functional Materials / Computational Simulation / Multiscale Mechanical Model / Synthesis of Microstructure |
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| Research Abstract |
Transformation induced plasticity (TRIP) models have been developed on the basis of probability of cross slip in the austenite matrix, which is dominated by the thermal fluctuation and accounting for the crystalline structure of both phases. The transformation models were introduced to crystalline plasticity theory to develop a constitutive equation account for the transformation in crystalline scale. The validity of the proposed constitutive equations has been verified through the reproducibility of the transformation dependent on the strain rate, temperature, stress, carbon content and crystalline structure. It is also revealed that the formability of the TRIP steel can be substantially improved without remarkable loss of stiffness by controlling the deformation process precisely. Then the constitutive equations are encoded in the finite element / finite element homogenization methods to establish a new simulation method for a finding of a forming process which saves energy effectively. The method is not applied to real forming process but to simple cases ; however, it suggests that a suitable control of temperature improves the formability without substantial loss of stiffness, and that the forming limit is able to improve when the microstructure of TRIP steels is artificially introduced and controlled. Furthermore, a microscopic model based on the molecular dynamic method and lattice instability concept has been developed for the evaluation of molecular scale transformation.
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