Development of Generalized Material Model by Multi-Scale Numerical Material Testing Considering Microscopic Deformation Mechanism

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03881
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Keio University
• Principal Investigator: OYA TETSUO 慶應義塾大学, 理工学部(矢上), 講師 (10410846)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 成形シミュレーション / 材料モデル / 結晶塑性 / 数値材料試験 / 加工硬化

Outline of Final Research Achievements

To improve the productivity of press forming of difficult-to-form materials, which have been increasingly used in recent years especially for car bodies, we have investigated the basic theory of forming simulation, and conducted research to realize support for forming process design. In order to achieve this, the following two subjects were addressed: (1) development of a generalized material model based on the microscopic structure of materials, and (2) establishment of a numerical material testing method that can support the use of the generalized material model. For (1), it was verified by using a finite element polycrystal model that the developed model can represent work-hardening of an arbitrary additional path. For (2), the effectiveness of the proposed method for fcc and hcp materials was confirmed by using actual material data.

Free Research Field

塑性力学

Academic Significance and Societal Importance of the Research Achievements

一般加工硬化モデルの検討のために有限要素多結晶モデルを用いた解析を行い，バックラッシモデルによるバウシンガー効果，最大林立転位モデルによる交差硬化の表現を実装し，微視的パラメータが及ぼす影響を文献値を用いて検証した．定量的な一致度には検討の余地があるものの，傾向としては材料の特徴をよく捉えており，提案モデルの有効性が示された．数値材料試験に関しては，単軸の材料試験結果を用いて同定されたパラメータを用いたモデルで二軸試験の応力ひずみ曲線を予測したところ良好な合致を示し，提案手法が実験の代替として機能することが確認できた．全体として当初の計画を概ね達成することができ，成形解析の高度化に寄与できた．