Quest for statistical mechanics theory of complex granular matter based on micro x-ray CT and particle-based simulation

2020 Fiscal Year Final Research Report

• Project/Area Number: 18KK0115
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 22:Civil engineering and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: Matsushima Takashi 筑波大学, システム情報系, 教授 (60251625)
• Co-Investigator(Kenkyū-buntansha): 高野 大樹 国立研究開発法人海上・港湾・航空技術研究所, 港湾空港技術研究所, 主任研究官 (80626218) ; 渡邊 保貴 一般財団法人電力中央研究所, 地球工学研究所, 主任研究員 (80715186)
• Project Period (FY): 2018-10-09 – 2021-03-31
• Keywords: 複雑粒状体 / x線マイクロCT / 低真空湿潤SEM / 個別要素法(DEM) / 統計力学 / マイクロメカニックス / 粒子形状 / 粘土凝集体

Outline of Final Research Achievements

This research project aimed at constructing a statistical mechanics theory of complex granular materials based on the results of state-of-the-art visualization techniques such as x-ray micro CT and low vacuum SEM as well as Discrete Element simulation. In particular, we focused on the effect of grain shape and adhesive force and (1) the relation between particle orientation statistics and the mechanical properties of the bulk material was obtained using x-ray micro CT observation of 3D printing ellipsoid grains of various shape, (2) statistical properties of grain shape-induced clustering was clarified by 2D DEM with elliptic particles, (3) cell stresses acting on the grain cell structure formed in 2D DEM packings were defined and its stress-structure correlation was confirmed, and (4) a SEM observation of submerged clay aggregates under shear was successfully made.

Free Research Field

地盤工学，粒状体力学

Academic Significance and Societal Importance of the Research Achievements

様々な分野で必要とされている複雑粒状体の力学特性評価について，統計力学的なアプローチを提案したことは，非平衡統計力学の基礎研究として学術的に重要である．特に粒子形状および粒子間付着力に関して，可視化実験より得られた定量的なデータ，また数値解析によって，形状起因のクラスタリングやセル応力について新たに得た知見は，地盤工学，粉体工学をはじめとした多くの分野に役立つものである．