Séminaire

Mardi 16 Juin 2026 à 11h00.

###### Shear-thickening in complex environments ###########

Alice Pelosse
(ESPCI Paris)

Salle de séminaires Lippmann

Invité(e) par
Nicolas Bain

présentera en 1 heure :

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The study of dense suspensions over the past decades has largely focused on shear thickening, a rheological property that emerges at high particle concentrations and under sufficiently large applied stresses. A common example is dense cornstarch in water, which can even support a person running across its surface without sinking. Unveiling the microscopic mechanisms at the origin of this behavior remains an active topic for experimentalists, numericans, and theoreticians.

In this talk, we will gain a better understanding of this phenomenon using strongly shear-thickening fumed-silica suspensions, by exploring how they behave when embedded in more complex environments.

First, by adding much larger particles (granules) to a shear-thickening suspension, I will show that shear thickening can be significantly softened. This points to a disruption of force-chain percolation induced by the presence of large granules within the small-particle, shear-thickening network.

Second, by immersing the suspension in a solid foam, and performing compression cycles, I will show that the resulting composite is strongly reinforced and that its mechanical response is not simply the sum of the responses of its constituents. Instead, a coupling between the fluid and solid phases must be taken into account, which depends on the state of the suspension entrapped in the foam cells.

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