Buckly-grains: a model system for elucidating interplay of extreme deformations and reconfigurations
| Project/Area Number |
22KF0084
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| Project/Area Number (Other) |
22F21315 (2022)
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| Research Category |
Grant-in-Aid for JSPS Fellows
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| Allocation Type | Multi-year Fund (2023)
Single-year Grants (2022) |
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| Section | 外国 |
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| Review Section |
Basic Section 13040:Biophysics, chemical physics and soft matter physics-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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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| Co-Investigator(Kenkyū-buntansha) |
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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| Project Period (FY) |
2023-03-08 – 2024-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2023: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2022: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | disordered materials / granular media / porous media / elasticity / experimental work / image analysis |
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| Outline of Research at the Start |
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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| Outline of Annual Research Achievements |
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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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
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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| Strategy for Future Research Activity |
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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Report
(1 results)
Research Products
(10 results)
