Force chains and contact network topology in packings of elongated particles

TL;DR

This study uses contact dynamic simulations to analyze how particle elongation influences force chains and contact network topology in 2D packings of elongated particles, revealing complex morphologies and evolving force distributions.

Contribution

It provides new insights into the impact of particle elongation on force networks and contact topology in granular packings, highlighting the transition of weak force networks from passive to active roles.

Findings

Force distributions broaden with increased particle elongation.

Strong force chains are mainly carried by side/side contacts aligned with principal stress.

Weak force networks evolve from passive stabilizers to active force transmitters.

Abstract

By means of contact dynamic simulations, we investigate the contact network topology and force chains in two-dimensional packings of elongated particles modeled by rounded-cap rectangles. The morphology of large packings of elongated particles in quasistatic equilibrium is complex due to the combined effects of local nematic ordering of the particles and orientations of contacts between particles. We show that particle elongation affects force distributions and force/fabric anisotropy via various local structures allowed by steric exclusions and the requirement of force balance. As a result, the force distributions become increasingly broader as particles become more elongated. Interestingly, the weak force network transforms from a passive stabilizing agent with respect to strong force chains to an active force-transmitting network for the whole system. The strongest force chains are carried by side/side contacts oriented along the principal stress direction.