Mechanochemical feedback drives complex inertial dynamics in active solids

TL;DR

This paper introduces a model of active solids with mechanochemical feedback, revealing how inertia-driven complex dynamics like chaos can emerge, informing design of ultrafast soft actuators.

Contribution

It demonstrates that mechanochemical feedback can induce autonomous inertial dynamics in active solids, a phenomenon less explored in overdamped systems.

Findings

Inertia-driven complex nonlinear dynamics emerge when feedback surpasses damping.

Active feedback can produce limit cycles and chaotic behavior.

Design principles for ultrafast soft actuators are proposed.

Abstract

Active solids combine internal active driving with elasticity to realize states with nonequilibrium mechanics and autonomous motion. They are often studied in overdamped settings, e.g., in soft materials, and the role of inertia is less explored. We construct a model of a chemically active solid that incorporates mechanochemical feedback and show that, when feedback overwhelms mechanical damping, autonomous inertial dynamics can spontaneously emerge through sustained consumption of chemical fuel. By combining numerical simulations, analysis and dynamical systems approaches, we show how active feedback drives complex nonlinear dynamics on multiple time-scales, including limit cycles and chaos. Our results suggest design principles for creating ultrafast actuators and autonomous machines from soft, chemically-powered solids.