Post-Doctoral Research Visit F/M Identification and modelling of fibre aggregates

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Testo originale dell'annuncio (in inglese)

Context: Under some specific stress conditions, random fibrous assemblies may spontaneously yield aggregates of finite size. In nature and industry, examples span from amyloid fibres and spherical packings of marino algae to dust bunnies, hair wisps and glass fibre flakes. In addition to the spontaneous emerging of a number of ’clumps’ or ’packets’, each one of this clumps exhibits some strong resistance against stretching or shearing, which can be viewed as the emerging of some cohesive behaviour at the macroscopic scale, although no cohesive contact is involved at the micro scale. This outstanding property is leveraged by birds for making nests, and starts being investigated by scientists and architects for building lightweight self-supporting structures at large scales. Besides the scarce physical studies and little understanding of all these complex phenomena, there are still very few attempts to reproduce them with simulation so far. Objectives: In this project our goal is to explore, understand and model the clumping behaviour that seems to spontaneously emerge in random assemblies of naturally curved fibres interacting solely through contact and friction. To that aim we shall leverage lab experiments and numerical tools (built in our team) to explore different scenarios, in 2D and in 3D, where clumping can be identified and characterised. In a second step, relying on these findings, a theoretical model for clumping will be investigated. This work will take advantage of the numerical Kirchhoff models for rods, contact detection, and frictional contact solvers developed by the Elan team, and additionally, we expect for this study to have an important experimental component to conceive novel setups and collect data to compare with simulations.