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Description
When slowly sheared, jammed packings respond elastically before yielding. This linear elastic regime becomes progressively narrower as the jamming transition point is approached, and rich nonlinear rheologies such as shear softening and hardening emerge. However, the physical mechanism of these nonlinear rheologies remains elusive. To clarify this, we numerically study jammed packings of athermal frictionless soft particles under quasi-static shear $\gamma$. We find the universal scaling behavior for the ratio of the shear stress $\sigma$ and the pressure $P$, independent of the preparation protocol of the initial configurations. In particular, we reveal shear-softening $\sigma/P \sim \gamma^{1/2}$ over an unprecedentedly wide range of strain up to the yielding point, which a simple scaling argument can rationalize [1].
Ref:
[1] T. Kawasaki and K. Miyazaki, Phys. Rev. Lett. 132, 268201 (2024).
