Effect of adhesive interaction on strain stiffening and dissipation in granular gels undergoing yielding

Non-linearity and energy dissipation in athermal disordered solids undergoing strain-induced yielding and fluidization remain poorly understood. Here, the authors use oscillatory shear rheology, in-situ imaging, and particle settling experiments to study yielding in granular suspensions of adhesive frictional particles finding a non-monotonic behavior of the normalized energy dissipation as a function of both applied strain amplitude and packing fraction values that can be explained by the critical jamming packing fractions encoding the interparticle interactions in the system Shear induced yielding in disordered solids, characterized by irreversibility and enhanced dissipation, is important for a wide range of industrial and geological processes. Although such phenomena in thermal systems have been extensively studied, they remain poorly understood for granular solids. Here, using oscillatory shear rheology we study energy dissipation in a disordered solid formed by dense granular suspensions of adhesive frictional particles. We find non-linear flow regimes showing intra-cycle strain stiffening and plasticity that strongly depend on both the applied strain amplitude and particle volume fraction, which can be captured by the normalized energy dissipation. Furthermore, in-situ optical imaging reveals irreversible particle rearrangements correlating with the spatio-temporal fluctuations in local velocity across the yielding transition. By directly measuring the critical jamming packing fraction using particle settling experiments, we propose a phase diagram that unravels the effect of inter-particle interactions on flow properties of the system for a large parameter space.