Oya, Tetsuo

写真a

Affiliation

Faculty of Science and Technology, Department of System Design Engineering （Yagami）

Position

Assistant Professor/Senior Assistant Professor

Related Websites
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Career 【 Display / hide 】

  • 2005.04
    -
    2008.03

    豊田工業大学

  • 2008.04
    -
    2010.03

    東京大学生産技術研究所

  • 2009.09
    -
    2011.03

    玉川大学

  • 2010.04
    -
    2014.03

    東京大学生産技術研究所

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Academic Background 【 Display / hide 】

  • 2000.03

    Tohoku University, Faculty of Engineering, 機械電子工学科

    University, Graduated

  • 2005.03

    Tohoku University, Graduate School, Division of Information Science, システム情報科学専攻

    Graduate School, Completed, Doctoral course

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Academic Degrees 【 Display / hide 】

  • Dr., Tohoku University, Coursework, 2005.03

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Research Areas 【 Display / hide 】

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Manufacturing and production engineering (Plasticity/Production Engineering/Processing Studies)

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Design engineering (CAE/Design Engineering)

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Research Keywords 【 Display / hide 】

  • Theory of plasticity

  • Forming analysis

  • Crystal plasticity

  • Numerical material test

  • Forming limit prediction

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Research Themes 【 Display / hide 】

  • Numerical material testing based on finite element polycrystal model, 

    2016
    -
    Present

  • Forming limit prediction based on bifurcation theory, 

    2014
    -
    Present

  • Cooling design based on multiphysics simulation, 

    2020
    -
    Present

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Papers 【 Display / hide 】

  • Formability mechanism of CFRP sheets using multiscale model based on microscopic characteristics of thermosetting resin

    Oya T., Nishino A.

    Multiscale and Multidisciplinary Modeling, Experiments and Design （Multiscale and Multidisciplinary Modeling, Experiments and Design)  4 （ 1 ） 65 - 76 2021.03

    　View Summary

    This study was undertaken to attempt to establish the press-forming of carbon fiber-reinforced plastic (CFRP) sheets through a forming simulation. Since press-forming induces large plastic deformation of a material, a reliable simulation requires accurate modeling of the plastic deformation of resin. However, there has been little research on the deformation mechanism of thermosetting resins under large plastic forming, which is targeted in this study, and therefore no appropriate plastic deformation model of a resin has been established. Thus, a new model was constructed for a thermosetting resin on the basis of plastic deformation characteristics considering the microscopic mechanism. In the proposed model, the breakage of molecular chains of a thermosetting resin is considered. A molecular dynamics simulation of epoxy resin determined the effect of this molecular chain breakage. It was confirmed that the proposed model can appropriately represent the mechanical characteristics of an actual thermosetting resin. Furthermore, using this model, the numerical analysis of a CFRP sheet through its representative volume element was carried out, and the result explained the improved formability of CFRP at high temperatures, as observed in related experiments.

  • Material testing of magnesium alloy AZ31B using a finite element polycrystal method based on a rate independent crystal plasticity model

    Vago G., Oya T.

    IOP Conference Series: Materials Science and Engineering （IOP Conference Series: Materials Science and Engineering)  967 （ 1 ）  2020.11

    ISSN  17578981

    　View Summary

    Magnesium and its alloys are attractive structural light materials because they have a high spe-cific strength and high specific stiffness. That is why their usage in high performance automotive and aerospace applications has been increased. However, their high anisotropy and low ductility could bring to forming failure, to avoid these a better accuracy for metal forming simulation is re-quired. The identification of macroscopic parameters is expensive due to the experiments needed to find them, the use of multi-scale approach allows to find parameters for the model through easier experiments. A finite element polycrystal method, based on a rate independent polycrystal plasticity model, is implemented in order to perform the material testing of a cast magnesium alloy AZ31B. The parameters of the model are adjusted to better fit the experimental data through a trial and error process.

  • Work-hardening behavior prediction model of arbitrary reloading process based on material crystallographic structure

    Oya T., Yanagimoto J., Ito K., Uemura G., Mori N.

    IOP Conference Series: Materials Science and Engineering （IOP Conference Series: Materials Science and Engineering)  967 （ 1 ）  2020.11

    ISSN  17578981

    　View Summary

    In the case of complex forming process that receives a secondary loading after the primary loading, it is necessary to appropriately represent the work-hardening state according to the forming history. Namely, it is necessary to accurately model complex forming process including reversal loading (Bauschinger effect) and orthogonal loading (cross-hardening). In this study, a composite anisotropic hardening expression based on the crystallographic structure using the finite element polycrystal model is proposed. Numerical investigations are conducted to consider the effectiveness of the proposed model. In which, an alternation rate is introduced to capture the activity of the slip systems to support the idea behind the proposed model. In addition, flow curves of the secondary loading are produced by the proposed model, which is compared with the conventional model.

  • Constitutive Equations Based on Non-associated Flow Rule for the Analysis of Forming of Anisotropic Sheet Metals

    Wu B., Ito K., Mori N., Oya T., Taylor T., Yanagimoto J.

    International Journal of Precision Engineering and Manufacturing - Green Technology （International Journal of Precision Engineering and Manufacturing - Green Technology)  7 （ 2 ） 465 - 480 2020.03

    ISSN  22886206

    　View Summary

    In this study, an anisotropic constitutive model based on the non-associated flow rule was developed for anisotropic sheet metals. This model was defined in the quadratic form of the Hill’s anisotropic function under a general three-dimensional stress condition. The anisotropic parameters for the yield function were identified using the directional planar yield stresses, bulge yield stress and shear yield stress, while those for the plastic potential function were identified using the directional r-values. A full expression related to the non-associated flow rule was applied and the model was implemented into the finite element code ABAQUS. A static-implicit analysis and the solid element were applied. Capability of the developed model for predicting the anisotropic behavior of sheet metal was investigated by considering two different sheet metal forming processes: cylindrical cup drawing of AA2090-T3, A6061P-T6 and SPCE; and hole expansion forming test of A6016-O. Cup heights and through-thickness strain distributions obtained from the simulations were compared with the experimental data. Results demonstrate that the developed material model considering 3D condition can improve accuracy of predicting the anisotropic behaviors. Furthermore, the simple formulations are efficient and user-friendly for computational analyses and solving the common industrial sheet metal forming problems.

  • Multiscale analysis of the formability of CFRP sheets subjected to warm forming with a temperature-dependent epoxy model

    Nishino A., Oya T.

    International Journal of Material Forming （International Journal of Material Forming)  12 （ 5 ） 793 - 800 2019.09

    ISSN  19606206

    　View Summary

    The press formability of cured CFRP (carbon fiber reinforced plastic) sheets composed of a thermoset polymer and continuous fibers was examined in this study. Press forming requires large plastic deformation, but CFRP is not sufficiently ductile in general. Therefore, it has been considered that CFRP is not suitable for press forming. However, recent experimental research has shown that the press formability of CFRP sheets is improved at 100 °C compared with that at room temperature. This finding indicates the possibility of the press forming of CFRP, but the temperature dependence of its formability has yet to be shown. To establish a press forming method for CFRP, an analytical study of its plastic deformation is essential. To determine the temperature dependence of the formability of CFRP, the strain-softening behavior of epoxy at warm temperatures was focused on in this study. This is because the mechanical characteristics of the polymer have a strong effect on the plastic deformation of CFRP. An approximated curve based on the temperature parameters was constructed to express the stress–strain relationship at different forming temperatures. Then, a model for press forming simulation was constructed to consider the effect of the mechanical characteristics of epoxy in CFRP. The approximated stress–strain curves at room temperature and 100 °C were applied to the model. Using this model, the stress distribution in CFRP sheets formed at each temperature has been shown, and the results clearly demonstrate that the formability of CFRP sheets is improved at higher temperatures.

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Reviews, Commentaries, etc. 【 Display / hide 】

  • Problems and Solutions of Plastic Constitutive Equation Based on Associated Flow Rule

    OYA Tetsuo, ITO Koichi

    Journal of the Japan Society for Technology of Plasticity (The Japan Society for Technology of Plasticity)  57 ( 662 ) 188 - 193 2016.03

    Article, review, commentary, editorial, etc. (scientific journal), Joint Work

  • On the Theory of Fracture Prediction in Metal Forming

    OYA Tetsuo, ITO Koichi

    Journal of the Japan Society for Technology of Plasticity (The Japan Society for Technology of Plasticity)  56 ( 658 ) 914 - 919 2015.11

    Article, review, commentary, editorial, etc. (scientific journal), Joint Work

  • Fundamentals in Generating Surfaces of Industrial Design (2) Expression by Subdivision Surfaces

    HIGASHI Masatake, OYA Tetsuo

    Journal of the Japan Society for Precision Engineering (The Japan Society for Precision Engineering)  80 ( 10 ) 914 - 917 2014.10

    Article, review, commentary, editorial, etc. (scientific journal), Joint Work

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Presentations 【 Display / hide 】

  • 繊維キンクの影響を考慮した熱硬化性CFRP薄板のプレス成形性解析

    林孝洋，大家哲朗

    第68回塑性加工連合講演会, 

    2017.11
    , 

    Oral presentation (general)

  • 逐次累積法に基づく有限要素多結晶モデルによる数値材料試験法(第2報)

    小野島慎，大家哲朗

    第68回塑性加工連合講演会, 

    2017.11
    , 

    Oral presentation (general)

  • 応力増分方向依存性と塑性異方性が破壊予測に及ぼす影響(第3報)

    大家哲朗，柳本潤，伊藤耿一，植村元，森尚達

    第68回塑性加工連合講演会, 

    2017.11
    , 

    Oral presentation (general)

  • 非関連流れ則に基づく異方性塑性構成式(第3報)

    OYA Tetsuo

    M&M2017 材料力学カンファレンス, 

    2017.10
    , 

    Oral presentation (general)

  • 逐次累積法に基づく有限要素多結晶モデルによる数値材料試験法

    荒木直之，大家哲朗

    平成29年度塑性加工春期講演会, 

    2017.06
    , 

    Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • 微視的変形機構を考慮したマルチスケール数値材料試験による一般化材料モデルの構築

    2018.04
    -
    2021.03

    日本学術振興会, Grant-in-Aid for Scientific Research, Research grant, Principal investigator

  • 高精度破断予測を目的とした異方性塑性構成式に関する研究

    2016.01
    -
    2016.12

    天田財団, 一般研究開発助成, Research grant, No Setting

  • 複層鋼板の多軸応力場における塑性変形挙動の解明と材料モデル構築

    2014.04
    -
    2016.03

    文部科学省・日本学術振興会, Grant-in-Aid for Scientific Research, Research grant, Principal investigator

  • 熱硬化CFRP の連続薄板化・100℃成形加工・塑性接合による極限軽量構造の具現化

    2014.04
    -
    2019.03

    文部科学省・日本学術振興会, Grant-in-Aid for Scientific Research, Research grant, Coinvestigator(s)

  • 複層鋼板の成形解析精度向上を目的とした材料モデル構築

    2014.04
    -
    2016.03

    日本塑性加工学, 日本塑性加工学会若手研究者研究助成, Research grant, Principal investigator

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Awards 【 Display / hide 】

  • 東京・南関東支部奨励賞

    2017.04, 日本塑性加工学会

    Type of Award： Award from Japanese society, conference, symposium, etc.

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Courses Taught 【 Display / hide 】

  • STRUCTURAL SYSTEM

    2022

  • SEMINAR IN SYSTEM DESIGN ENGINEERING

    2022

  • NONLINEAR SOLID MECHANICS

    2022

  • MODELING OF STATICAL AND DYNAMICAL PHENOMENA

    2022

  • MATHEMATICAL PROGRAMMING FOR DESIGN AND PLANNING

    2022

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Courses Previously Taught 【 Display / hide 】

  • デザインリテラシー演習

    Keio University

    2018.04
    -
    2019.03
    , 

    Spring Semester, Seminar, Lecturer outside of Keio, 70people

  • 非線形固体力学

    Keio University

    2018.04
    -
    2019.03
    , 

    Autumn Semester, Lecture, Lecturer outside of Keio, 10people

  • 設計・計画の最適化数理

    Keio University

    2018.04
    -
    2019.03
    , 

    Autumn Semester, Lecture, Lecturer outside of Keio, 50people

  • 構造システム工学

    Keio University

    2018.04
    -
    2019.03
    , 

    Autumn Semester, Lecture, Within own ｆaculty, 40people

  • 自然科学実験物理学編

    Keio University

    2018.04
    -
    2019.03
    , 

    Autumn Semester, Laboratory work/practical work/exercise, Lecturer outside of Keio

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Memberships in Academic Societies 【 Display / hide 】

  • 自動車技術会, 

    2014.06
    -
    Present

  • 日本設計工学会, 

    2012.05
    -
    Present

  • 日本鉄鋼協会, 

    2012.03
    -
    Present

  • 日本塑性加工学会, 

    2008.05
    -
    Present

  • 精密工学会, 

    2005.06
    -
    Present

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Committee Experiences 【 Display / hide 】

  • 2015.04
    -
    Present

    編集委員，校閲委員, 日本塑性加工学会

  • 2018.04
    -
    Present

    庶務監事，商議員, 日本塑性加工学会　東京・南関東支部

  • 2016.04
    -
    Present

    創形創質工学部会・運営委員, 日本鉄鋼協会

  • 2012.05
    -
    2020.05

    校閲委員，特別投稿担当幹事, 日本設計工学会

  • 2012.03
    -
    2022.03

    創形創質部会若手フォーラム幹事，座長, 日本鉄鋼協会

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