Stress localization, cooperative dynamics and yielding in poorly connected soft solids.

Stress localization, cooperative dynamics and yielding in poorly connected soft solids.
Emanuela Del Gado, Georgetown University
Date and time: Thu, Dec 04, 2014 - 11:21am
Refreshments at 11:06am
Location: LGRT 1033
Category: Condensed Matter Seminar
Abstract:

Colloidal gel networks are disordered elastic solids that can form even in extremely dilute particle suspensions. With interaction strengths comparable to the thermal energy, their stress-bearing network can locally restructure via breaking and reforming interparticle bonds. This allows for yielding, self-healing, and adaptive mechanics under deformation. Designing such features requires controlling stress transmission through the complex structure of the gel and this is challenging because the link between local restructuring and overall response of the network is still missing. I will discuss how numerical simulations of a minimal model can allow for insight into this link. Starting from the self-assembly of the gel, we have analyzed the cooperative dynamics emerging from its mesoscale organization, to show that consequences of local bond breaking propagate along the gel network over distances larger than the average mesh size. Under deformation, our space-resolved analysis of strains and stresses unravel how a strong localization of tensile stresses may trigger the yielding of the gel and, at low enough share rate, eventually damage its structure.