Ultraslow settling kinetics of frictional cohesive powders

Abstract

Using discrete element method simulations, we show that the settling of frictional cohesive grains under ramped-pressure compression exhibits strong history dependence and slow dynamics that are not present for grains that lack either cohesion or friction. Systems prepared by beginning with a dilute state and then ramping the pressure to a small positive value $P_{\mathrm{final}}$ over a time ${\tau }_{\mathrm{ramp}}$ settle at packing fractions given by an inverse-logarithmic rate law, ${\varphi }_{\mathrm{settled}}({\tau }_{\mathrm{ramp}})={\varphi }_{\mathrm{settled}}(\infty )+A/[1+B\ln (1+{\tau }_{\mathrm{ramp}}/{\tau }_{\mathrm{slow}})]$. This law is analogous to the one obtained from classical tapping experiments on noncohesive grains, but crucially different in that ${\tau }_{\mathrm{slow}}$ is set by the slow dynamics of structural void stabilization rather than the faster dynamics of bulk densification. We formulate a kinetic free-void-volume theory that predicts this ${\varphi }_{\mathrm{settled}}({\tau }_{\mathrm{ramp}})$, with ${\varphi }_{\mathrm{settled}}(\infty )={\varphi }_{\mathrm{ALP}}$ and $A={\varphi }_{\mathrm{settled}}(0)-{\varphi }_{\mathrm{ALP}}$, where ${\varphi }_{\mathrm{ALP}}\equiv .135$ is the ``adhesive loose packing'' fraction found by Liu \textit{et al.} [W.\ Liu, Y.\ Jin, S. Chen, H.\ A.\ Makse and S.\ Li, \textit{Soft Matt.} \textbf{13}, 421 (2017)].

arXiv commentSupplemental Material available upon request

References in corpus (25)

• Jamming at Zero Temperature and Zero Applied Stress: the Epitome of Disorder
• Granular flow down an inclined plane: Bagnold scaling and rheology
• A model for collisions in granular gases
• Jamming transition in emulsions and granular materials
• Bridging the rheology of granular flows in three regimes
• Jamming of frictional spheres and random loose packing
• Jamming transitions in amorphous packings of frictionless spheres occur over a continuous range of volume fractions
• Onset of mechanical stability in random packings of frictional spheres
• Computer simulation of model cohesive powders: influence of assembling procedure and contact laws on low consolidation states
• Nonperturbative effect of attractive forces in viscous liquids
• Slow relaxation in granular compaction
• Loose packings of frictional spheres
• The jamming transition and new percolation universality classes in particulate systems with attraction
• Statistical Mechanics of Vibration-Induced Compaction of Powders
• Computer simulation of model cohesive powders: Plastic consolidation, structural changes and elasticity under isotropic loads
• Adhesive Loose Packings of Small Particles
• Sticky Matter: Jamming and rigid cluster statistics with attractive particle interactions
• Granular packings with sliding, rolling and twisting friction
• Equation of state for random sphere packing with arbitrary adhesion and friction
• Pore Stabilization in Cohesive Granular Systems
• Disordered jammed packings of frictionless spheres
• The effect of contact torques on porosity of cohesive powders
• Elasticity of Jammed Packings of Sticky Disks
• Frictional Granular Matter: Protocol Dependence of Mechanical Properties
• Record Dynamics in the Parking Lot Model