Unconventional rheological properties in systems of deformable particles

TL;DR

This paper reveals unique rheological behaviors in soft-deformable particle systems, showing shear weakening linked to shape-dependent energy and tetratic order, with reversible contact networks but irreversible microscopic dynamics.

Contribution

It uncovers unconventional shear weakening and memory effects in deformable particle systems, highlighting the role of shape-dependent energy and tetratic order in their rheology.

Findings

Shear weakening transition occurs at large strains.

Mechanical energy increases while shear stress drops.

Contact networks are reversible under strain reversal.

Abstract

We demonstrate the existence of unconventional rheological and memory properties in systems of soft-deformable particles whose energy depends on their shape, via numerical simulations. At large strains, these systems experience an unconventional shear weakening transition characterized by an increase in the mechanical energy and a drastic drop in shear stress, which stems from the emergence of short-ranged tetratic order. In these weakened states, the contact network evolves reversibly under strain reversal, keeping memory of its initial state, while the microscopic dynamics is irreversible.