Séminaire du LPTMS: Mehdi Bouzid

Quand

03/04/2018    
11:30 - 12:00

LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay
15 Rue Georges Clemenceau, Orsay, 91405
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Athermal analogue of sheared colloidal suspensions

Mehdi Bouzid (LPTMS, Université Paris-Sud)

Sand-piles, window glass, tomato ketchup, are three materials that would not necessarily strike the larger public for their similarities. However, they take part of one of the most lingering enigma of condensed matter physics as they are examples of fluids undergoing dynamical arrest and becoming solid in a way essentially different from a thermodynamic phase transition. Such complex fluids, developing a yield-stress and becoming very hard solids (metallic or oxide glasses) or soft glassy materials (colloidal pastes, granular packing, polymer melts …), are of central importance in statistical physics, material science or chemical engineering. In this talk I will highlight an analogy between the rheology of Brownian and  non-Brownian  suspensions, we show that these systems can be described by a Herschel-Bulkley law as soon as the shear rate and shear stress  are respectively normalized by an energy scale and a microscopic time of reorganization, which are both functions of the normal confinement stress. The pressure-controlled approach, originally developed for granular flows, reveals a striking physical analogy between the colloidal glass transition and the granular jamming transition.

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