Fragility in shear jamming of dense frictional suspensions

Particulate systems often undergo fluid-solid transition. The packing fraction that corresponds to this particular transition is often found to be protocol dependent. In case of frictional particulate systems, starting from a force-free random configuration at φ > φ_sj^μ and subjected to shear by constant stress, some rearrangements (i.e., flowing) may occur before getting jammed. Such shear jammed states may flow again by changing the direction of the applied stress; such states are termed "fragile." We quantify this fragility with a stress reversal simulation and identify the point where the fragility vanishes as the isotropic jamming point φ_j^μ. We also present a shear-jamming phase diagram of stress-dependent suspension model with a critical-load friction model.