Soutenance de thèse: Samuel Cazayus-Claverie

Effect of residual stress on the elasticity of fiber networks

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Samuel Cazayus-Claverie

 

Jury:

Anaël Lemaître – rapporteur

Chaouqi Misbah – rapporteur

Giuseppe Foffi – examinateur

Cécile Leduc – examinatrice

Martin Lenz – directeur de thèse

Raphaël Voituriez – examinateur

Resumé:

Cells are the basic units of all living organisms. Eukaryotic cells are stuctured on top of a scaffold of fibers ranging from stiff microtubules to semiflexible actin : the cytoskeleton. As such the cytoskeleton is involved into a broad family of processes of translocation and deformation of cells, it is also responsible for cells mechanical stiffness. The actin filaments into cytoskeleton can be cross-linked into bundles built of as much as 30 parallel filaments, but filaments can get bound at a finite angle also. These processes are in competition during network’s self-assembly and result in strong residual stresses. In this thesis, we study the effect of these residual stresses on the elasticity of fiber networks in 2 dimensions of space. We develop an original method to compute stress on the boundaries of a network and its
elastic moduli. We find that residual stress induces a  stiffening in the infinitesimal response of the network. Residual stress also affects the non linear response of the network : we find that it makes the network unstable under compression, and that they control the onset of non linear response to shear.

 


Date/Time : 25/02/2020 - 14:30

Location : Petit amphi, bâtiment Pascal n° 530

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