Force Dynamics in Weakly Vibrated Granular Packings

TL;DR

This paper investigates the complex force behaviors in granular materials under weak vertical vibrations, revealing nonlinear and hysteretic force dynamics even without significant grain motion, influenced by force-network interactions.

Contribution

It uncovers the nonlinear and hysteretic force responses in granular packings under weak vibrations, highlighting force-network effects independent of grain motion.

Findings

Force dynamics vary with packing density and vibration frequency.

Hysteretic behavior indicates complex force-network interactions.

Nonlinear force responses occur even with minimal grain movement.

Abstract

The oscillatory force F_b^ac on the bottom of a rigid, vertically vibrated, grain filled column, reveals rich granular dynamics, even when the peak acceleration of the vibrations is signicantly less than the gravitational acceleration at the earth's surface. For loose packings or high frequencies, F_b^ac 's dynamics are dominated by grain motion. For moderate driving conditions in more compact samples, grain motion is virtually absent, but F_b^ac nevertheless exhibits strongly nonlinear and hysteretic behavior, evidencing a granular regime dominated by nontrivial force-network dynamics.