Minimal model of an active solid deviates from equilibrium mechanics

TL;DR

This paper investigates the mechanical behavior of a one-dimensional active solid with nonlinear springs, revealing how activity and noise influence deformation, and suggesting potential for designing tunable active metamaterials.

Contribution

It introduces a minimal model for active solids with nonlinear springs, showing how activity and noise affect deformation differently than in passive systems.

Findings

Active solids with linear springs show deformation independent of activity.

Nonlinear springs cause active solids to deform less than passive ones under stress.

Deformation varies with activity and rotational noise, indicating tunable stiffness.

Abstract

In this work, the mechanical response oF an one-dimensional active solid -- defined as a network of active stochastic particles interacting by nonlinear hard springs -- subject to an external deformation force, is numerically studied and rationalized with a minimal model. It is found that an active solid made of linear springs and subject to an external stress, presents an average deformation which is independent of the system's activity. However, when the active solid is made of nonlinear hard springs, the solid's average deformation decreases with respect to a passive system under the same conditions, and as a function of activity and rotational noise in the system. The latter result may shed light on new ways to creating an active metamaterial, which could tune its stiffness by moving either its activity or rotational noise.