| 研究課題/領域番号 |
22KF0084
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| 補助金の研究課題番号 |
22F21315 (2022)
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 基金 (2023)
補助金 (2022) |
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| 応募区分 | 外国 |
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| 審査区分 |
小区分13040:生物物理、化学物理およびソフトマターの物理関連
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| 研究機関 | 東京大学 |
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研究代表者 |
竹内 一将 東京大学, 大学院理学系研究科(理学部), 准教授 (50622304)
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| 研究分担者 |
POINCLOUX SAMUEL 東京大学, 大学院理学系研究科(理学部), 外国人特別研究員
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| 研究期間 (年度) |
2023-03-08 – 2024-03-31
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| 研究課題ステータス |
交付 (2023年度)
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| 配分額 *注記 |
2,300千円 (直接経費: 2,300千円)
2023年度: 1,100千円 (直接経費: 1,100千円)
2022年度: 1,200千円 (直接経費: 1,200千円)
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| キーワード | disordered materials / granular media / porous media / elasticity / experimental work / image analysis |
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| 研究開始時の研究の概要 |
To investigate the role of large compressibility in the development of flowing instabilities, we explore experimentally the mechanical response of an assembly of ring-shaped grains, a model system at the border between porous and granular media. Under compression, the rings show heterogeneous and large deformations, which promote the development of irreversible displacements under oscillatory shear. While structural deformations seem to lead to system spanning reorganisations, shape fluctuations may act as an apparent activity leading to diffusive behaviours.
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| 研究実績の概要 |
The AY2022 was devoted to the implementation of the experimental set-up and development of the analysis tools.
Experimental achievements (~6 months). Fabrication of the compressible ring-shaped grains using 3D-printing and moulding. Careful selection and testing of the ring material was necessary to avoid introducing undesirable plastic of viscoelastic deformations. Adaptation and improvement of the shear experimental set-up to acquire the global shear and compression force. Implementation of a Labview process to simultaneously control and synchronize the driving motor, the camera, and the force sensors. Acquisition of datasets varying both the shear amplitude and density of rings.
Analysis achievements (~5 months). Development of an image analysis framework. The method detects and separates each ring and measures their tracked position, shape, and neighbourhood. We combine Lagrangian and Eulerian analysis. From these measurements, we explore the interplay between ring deformations and irreversible displacements. Rationalization of the mechanical response of a single ring to indentation by combining a finite element approach using COMSOL and a 1D analytical development.
Presentations and publications (~1 month). Presentation of the preliminary results in domestic and international conferences, receiving positive and valuable feedbacks from the community. Outreach conferences to High school students (Science Dialogue) and French researchers. Publication (2) and submission (1) of research projects started before the JSPS fellowship.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
During this first AY2022 academic year, we successfully achieved the experimental and analytical objectives of the initial plan. We managed to fabricate rings with adequate mechanical properties and high reproducibility, and to set-up an oscillatory shear mechanical platform. Some technical difficulties were encountered to include force measurements to the experiments, but they have been understood and will be addressed in early AY2023.
On the analysis side, we successfully developed an image analysis process to detect all quantities of interest (position, shape, and neighbourhood) from snapshots of the ring assemblies. Successful analysis required additional steps in the fabrication methods of the rings. Using finite element and analytical approaches, we also linked the geometrical of a ring under indentation to its mechanical properties.
Finally, inspired by previous studies on granular media, we identified density and shear amplitude as the two main parameters of our experiments. We then systematically varied these two parameters in our experiments and analysed the corresponding datasets.
The progress made during the AY2022 can be attested by the international (3) and domestic (1) conferences at which this work has been presented.
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| 今後の研究の推進方策 |
The AY2023 will focus on clarifying the encouraging results obtained in AY2022, report them in publications and at conferences, and finally explore how they can be applied to geological or biological situations.
1. (~ 3 months) Acquisition and analysis of a new extensive dataset. We will finish setting-up an upgraded version of the experiments, which allows to record global force measurements and local deformations simultaneously and reliably. We will then acquire an extensive dataset varying continuously the two main parameters of interest: the shear amplitude and the density of rings.
2. (~ 3 month) Redaction of a least one article summarizing the main results. We believe that the originality and the precision of the results would qualify them for a high-impact journal. Participation to international and domestic conferences to share and advertise our work.
3. (~ 6 months) We then aim at exploring in what extent compressibility may play a role in geological or biological contexts. In the context of landslide instabilities, we will explore how compressibility affects the angle of repose of a ring assembly under compression. For this purpose, we will build a simple experimental set-up allowing to compress a ring assembly under rotating gravity. In a biological context, we will deepen comparison of ring assemblies with epithelial cell assemblies by adding self-activity to the rings. Autonomous robots with persistent movement will be imbedded in a compressible shell and then placed in a fixed volume enclosure to observe their dynamics.
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