Crystal-plasticity modeling of time-dependent deformation behavior of metallic sheets and its application to press forming simulations

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03428
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Material processing/Microstructural control engineering
• Research Institution: Kyoto University
• Principal Investigator: Hama Takayuki 京都大学, エネルギー科学研究科, 准教授 (10386633)
• Co-Investigator(Kenkyū-buntansha): 高村 正人 国立研究開発法人理化学研究所, 光量子工学研究センター, 上級研究員 (00525595) ; 宅田 裕彦 京都大学, エネルギー科学研究科, 教授 (20135528) ; 袴田 昌高 京都大学, エネルギー科学研究科, 准教授 (30462849)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 結晶塑性有限要素法 / 時間依存変形 / 板材成形 / 環境調和型金属

Outline of Final Research Achievements

The purpose of this study was to comprehensively study time-dependent deformation behavior of metallic sheets and to model the behavior by using crystal-plasticity models. Specifically, first, a crystal plasticity model was developed to reproduce stress relaxation and creep behavior of commercially-pure titanium sheets. The developed model was then used to simulate the effect of time-dependent deformation behavior on the press formability of commercially-pure titanium sheets. Time-dependent deformation, where the shape of a press-formed part gradually changed after press forming, was well reproduced by using the developed model, and moreover, the underlying deformation mechanism of this behavior was also discussed. It is expected that the achievements of this work would be useful to extend use of environmentally-friendly metals, including titanium sheets, which would eventually lead to weight reduction of vehicles.

Free Research Field

機械工学

Academic Significance and Societal Importance of the Research Achievements

本研究では，輸送機器の軽量化を促進しうる材料として期待されている環境調和型金属板の時間依存変形特性を系統的に調査し，またその理論モデルを構築した点が大きな学術的意義の一つである．具体的には，工業用純チタン板を対象として時間依存変形を予測可能な結晶塑性解析技術を開発し，またそれをプレス成形解析にまで応用したことは世界的にも初めての学術的成果である．本研究の成果を通して，環境調和型金属のプレス成形性向上とそれによるこれら金属の利用拡大，またその結果として輸送機器軽量化による地球環境問題への貢献が期待され，社会的にも大きな意義を持つ．