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Jacob D. Thompson

Publications and source records attributed to Jacob D. Thompson.

2 recordsLinked to original sources

Critical scaling for yield is independent from distance to isostaticity

Using discrete element simulations, we demonstrate that critical behavior for yielding in soft disk and sphere packings is independent of distance to isostaticity over a wide range of dimensionless pressures. Jammed states are explored via quasistatic shear at fixed pressure, and the statistics of the dimensionless shear stress $μ$ of these states obey a scaling description with diverging length scale $ξ\propto |μ-μ_c|^{-ν}$. The critical scaling functions and values of the scaling exponents are nearly independent of distance to isostaticity despite the large range of pressures studied. Our results demonstrate that yielding of jammed systems represents a distinct nonequilibrium critical transition from the isostatic critical transition which has been demonstrated by previous studies. Our results may also be useful in deriving nonlocal rheological descriptions of granular materials, foams, emulsions, and other soft particulate materials.

cond-mat.soft

Critical scaling near the yielding transition in granular media

We show that the yielding transition in granular media displays second-order critical-point scaling behavior. We carry out discrete element simulations in the low inertial number limit for frictionless, purely repulsive spherical grains undergoing simple shear at fixed nondimensional shear stress $Σ$ in two and three spatial dimensions. To find a mechanically stable (MS) packing that can support the applied $Σ$, isotropically prepared states with size $L$ must undergo a total strain $γ_{\rm ms}(Σ,L)$. The number density of MS packings ($\propto γ_{\rm ms}^{-1}$) vanishes for $Σ> Σ_c \approx 0.11$ according to a critical scaling form with a length scale $ξ\propto |Σ- Σ_c|^{-ν}$, where $ν\approx 1.7-1.8$. Above the yield stress ($Σ>Σ_c$), no MS packings that can support $Σ$ exist in the large system limit, $L/ξ\gg 1$. MS packings generated via shear possess anisotropic force and contact networks, suggesting that $Σ_c$ is associated with an upper limit in the degree to which these networks can be deformed away from those for isotropic packings.

cond-mat.soft