Establishment of mechanical modeling process of nonuniform deformation and development of deformation concentration-reduced material

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03844
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Osaka City University
• Principal Investigator: Uchida Makoto 大阪市立大学, 大学院工学研究科, 准教授 (90432624)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 不均一変形 / 不均質構造 / DIC / FEM / 均質化法 / ひずみこう配 / 非局所

Outline of Final Research Achievements

Engineering materials typically have a heterogeneous microstructure. When the size difference between micro and macrostructure is small, the interaction of nonuniform deformation in both scales induces the size effect. In this study, the direct mechanical modeling process of the non-uniform deformation characterized by the material microstructure with a finite size is established using the quantitatively evaluated strain fields. It will contribute the development of the engineering material suppressing the deformation concentration.
Experimental and numerical studies on the tensile test of polycrystalline specimens having a curved gage section were performed to discuss the interaction between micro and macroscopic non-uniform deformation. From the series of the obtained results, we proposed the nonlocal mechanical model, which can represent size-dependent non-uniform deformation, using the plastic compliance gradient and stress field for the finite region of the heterogeneous material.

Free Research Field

固体力学

Academic Significance and Societal Importance of the Research Achievements

材料の損傷の前駆現象である変形集中を抑制することは工業製品の安全性を高める上で極めて効果的である．有限要素法を用いれば，材料の応力ひずみ関係から連続体スケールの不均一変形を予測することが可能になるが，製品寸法が微小になるほど，材料の微視構造が製品の変形状態に影響することによって予測精度が低下する．本研究では，そのような材料の微視構造が誘発する不均一変形を実験から定量化し，それを予測可能なモデルを提案した．本研究により鰓得た一連の成果は，材料の不均一変形の予測精度を改善するとともに，変形集中抑制を実現可能な材料開発に貢献するものと確信している．