Pentagon deposits unpack under gentle tapping

TL;DR

This study investigates how regular pentagon particles in a confined space respond to vertical tapping, revealing unique arch formation and packing behavior compared to disks, especially under gentle tapping conditions.

Contribution

It provides new insights into the packing dynamics of non-circular particles, highlighting the impact of particle shape on arch formation and packing density under tapping.

Findings

Pentagons form fewer arches than disks.

Arch size increases as tapping amplitude decreases.

Packing fraction decreases with gentle tapping for pentagons.

Abstract

We present results from simulations of regular pentagons arranged in a rectangular die. The particles are subjected to vertical tapping. We study the behavior of the packing fraction, number of contacts and arch distributions as a function of the tapping amplitude. Pentagons show peculiar features as compared with disks. As a general rule, pentagons tend to form less arches than disks. Nevertheless, as the tapping amplitude is decreased, the typical size of the pentagon arches grows significantly. As a consequence, a pentagon packing reduces its packing fraction when tapped gently in contrast with the behavior found in rounded particle deposits.