Title: Yielding and fluidization in sheared and active amorphous solids

Speaker: Srikanth Sastry (Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore)

Abstract:

The mechanical behaviour of a wide range of amorphous solids, from molecular glasses, soft materials such as polymeric glasses, colloids, to granular matter, is of interest in diverse contexts, from investigations of biological assemblies, glasses as materials, to geophysical phenomena. The nature of plasticity and the eventual yielding behaviour of amorphous solids have been investigated extensively in recent years through computer simulations and statistical mechanical approaches. In particular, under cyclic shear deformation, yielding is revealed to be a discontinuous transition, with a strong dependence of the degree of annealing of the glasses. An important phenomenon in solids subjected to cyclic loading is that of fatigue failure, which occurs after a number of cycles of loading, with the number of cycles diverging as a limiting amplitude is approached from above. The characterization of these phenomena from computer simulations will be presented. Interestingly, several of the key features of the transition from solid to fluidized states are also exhibited when dense assemblies of particles are subjected to driving by active forces. Results illustrating the detailed analogy of these phenomena, as well as a striking dependence of the fluidization of active particles on confinement, will be summarized.

This seminar will take place in room A1.06