Designing principles of mechanical metamaterials based on the studies of heterogeneous elastic materials

2023 Fiscal Year Final Research Report

• Project/Area Number: 18K13519
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13040:Biophysics, chemical physics and soft matter physics-related
• Research Institution: Keio University (2021-2023); Ritsumeikan University (2018)
• Principal Investigator: Sano Tomohiko 慶應義塾大学, 理工学部(矢上), 講師 (00791378)
• Project Period (FY): 2021-03-01 – 2024-03-31
• Keywords: 力学と幾何学 / 弾性体 / ソフトマテリアル / ソフトロボティクス

Outline of Final Research Achievements

The purpose of this study was to experimentally clarify the mechanical response of an assembly of shell structures, where the microstructure is a precisely designable shell. Among shell structures, an assembly of curved beam structures was considered. Cylindrical shells with uniform spontaneous curvature were created, and the mechanical properties of the aggregates were clarified by observing the large deformation when two cylindrical shells are pressed against each other. It was found that the shells fit into each other and can compress with a low overall load. In other words, shell aggregates are found to be useful as buffer materials based on geometry.

Free Research Field

ソフトマター，材料力学

Academic Significance and Societal Importance of the Research Achievements

シェル集合体は緩衝材として使用することが可能である．例えば圧縮の最大荷重を決めておき、その荷重に達するのに必要な最大変位を定めればシェルのデザインを決定できる．そして圧縮と展開のサイクル試験におけるエネルギー散逸率は形状にあまり強く依存せずロバストな散逸性能が引き出せる。上記の実験結果はコンピュータグラフィクス計算によるシミュレーションと正確な一致を見せている．実験でその妥当性を検証した上で，実験で変化させることが難しい摩擦係数依存性も明らかにした．コンピュータグラフィクスが材料変形の予測に利用できることを示しており，材料力学の新しい研究の方向性を示したとも言える．