Kondou Ryouji

写真a

Title

Associate Professor

Researcher Number(JSPS Kakenhi)

80404549
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Current Affiliation Organization 【 display / non-display 】

  • Duty   University of the Ryukyus   Faculty of Engineering   School of Engineering_Energy and Environment Program   Associate Professor  

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Academic degree 【 display / non-display 】

  • Okayama University -  Doctor of Engineering

  • University of the Ryukyus -  Master (Engineering)

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External Career 【 display / non-display 】

  • 2007.08
    -
    2017.03

    University of the Ryukyus, Faculty of Engineering, Department of Mechanical Systems Engineering, Mechanics and System Control, Associate Professor  

  • 2017.04
    　
    　

    University of the Ryukyus, Faculty of Engineering, Department of Engineering, Associate Professor  

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Research Interests 【 display / non-display 】

  • Plasticity,Deformation Processing

  • 計算力学

  • 材料力学

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Research Areas 【 display / non-display 】

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Mechanics of materials and materials

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Research Theme 【 display / non-display 】

  • Multi-Scale Analysis of Slip Deformation and Dislocation in Polycrystalline Material

  • Multi-Scale Analysis of Fatigue and Dislocation in Polycrystalline Material

  • Multiphysics Analysis of Phase-Transformation and Elastic-plastic deformation in Polycrystalline Material

  • Development of Grain Refinement and Texture Control Technique of Polycrystalline Material

  • Evaluation of Strain and Deformation of Micro Structure of Human Body

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Published Papers 【 display / non-display 】

  • Effect of Overload and Underload on Subsequent Deformation Behavior during Cyclic Deformation

    KONDOU Ryouji, YAMA Katsunari

    Journal of the Society of Materials Science, Japan ( The Society of Materials Science, Japan )  71 ( 2 ) 159 - 166   2022.02

    Type of publication: Research paper (scientific journal)

    　View Summary

    <p>A multi-scale analysis of elasto-plastic deformation and dislocation movement and accumulation of tri-crystalline models during cyclic deformation was performed. The accumulation of dislocations in geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) was investigated in detail. Experimental observations have shown that fatigue life and fatigue crack propagation are also deteriorated when the material is subjected to overload or underload. However, in the microscopic and mesoscopic regions, where the effects of the crack tip shape change are not related to the size of the crack tip, a different phenomenon is essentially occurring. In this paper, the effects of overload and underload are investigated using a simple model without a crack. From the analysis results, it was found that the dislocation structure generated in the material subjected to overload or underload affects the subsequent deformation behavior. However, even though the absolute values are the same, the effects of overloading and underloading on the subsequent deformation are different, and underloading increases the non-uniformity of the subsequent deformation, which is on the dangerous side, while overloading decreases with increasing the number of repetitions. </p>

  • Crystal plasticity analysis of change in incompatibility and activities of slip systems in α-phase of Ti alloy under cyclic loading

    Yoshiki Kawano, Tetsuya Ohashi, Tsuyoshi Mayama, Ryoji Kondou

    International Journal of Mechanical Sciences ( International Journal of Mechanical Sciences )  146-147   475 - 485   2018.10 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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  • Evolution of Dislocation Patterns in a Tricrystal Model Subjected to Cyclic Loading

    Tetsuya Ohashi and Ryouji Kondou

    Philosophical Magazine ( その他の出版社 )  93 ( 4 ) 366 - 387   2013.03 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

  • Effects of Torsional Plastic Deformation on Fatigue Strength in Copper and Aluminum

    Chobin Makabe, Kazuo Kuniyoshi, Masaki Fujikawa, Ryoji Kondou and Daisaku Shinohara

    Key Engineering Materials ( その他の出版社 )  452-453   597 - 600   2011 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

  • Geometrically necessary dislocation structure organization in FCC bicrystal subjected to cyclic plasticity

    Tsuyoshi. Mayama, Tetsuya Ohashi, Ryouji Kondou

    International Journal of Plasticity ( その他の出版社 )  25   2122 - 2140   2009.10 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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Presentations 【 display / non-display 】

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SDGs 【 display / non-display 】

  • 金属多重結晶のすべり変形と転位の運動・蓄積のマルチスケール解析
    金属多重結晶のすべり変形と転位の運動・蓄積のマルチスケール解析
    金属多重結晶の相変態と弾塑性変形のマルチフィジックス解析
    金属多重結晶の集合組織制御と結晶粒微細化を伴う塑性加工技術の開発

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