Creep motion of an intruder within a granular glass close to jamming

TL;DR

This study experimentally examines how an intruder moves within a vibrated granular material near jamming, revealing a transition from rapid to intermittent creep motion characterized by crackling noise and heterogeneous force chain patterns.

Contribution

It provides new insights into the critical dynamics and fluctuation behavior of intruder motion near the jamming transition in granular materials.

Findings

Intruder exhibits rapid movement at low packing fractions.

Above a critical packing fraction, motion becomes intermittent with crackling noise.

Transition separates free volume rearrangements from force chain-dominated dynamics.

Abstract

We investigate experimentally the dynamics of an intruder dragged by a constant force in an assembly of horizontally vibrated grains close to jamming. At moderate packing fractions, the intruder moves rapidly as soon as the force is applied. Above some threshold value of the packing fraction which increases with the applied force, the intruder exhibits an intermittent creep motion with strong fluctuations reminiscent of a crackling noise signal. These fluctuations behave in a critical manner at the jamming transition unveilled in a previous study. The transition separates a regime where the intruder motion is dominated by local free volume rearrangements from a regime where the instantaneous displacement field is strongly heterogeneous and resemble the force chains patterns observed in dense granular packings.