Frustrated Active Metamaterial

Metamaterials are engineered to exhibit exceptional properties by manipulating their micro- or nano-scale structural arrangements. While they have seen applications in optics, electronics, and acoustics, mechanical metamaterials have recently gained attention due to their unique stress-strain response. Introducing activity into these materials, such as mechanical motors or electronic drivers, breaks momentum conservation and paves the way for non-reciprocal interactions. In this work, we explore the dynamics of topological nonlinear waves in frustrated active metamaterials, focusing on systems composed of non-reciprocal active units interacting through geometrically derived topological constraints. These robotic topological metamaterials display emergent global phenomena such as noise-driven bi-stable switching, resulting from the interplay between their structural and active components.

Our study presents a combination of numerical simulations, experiments, and theoretical models to uncover distinct emergent states and bi-stable behavior in these materials. Notably, non-reciprocity is shown to play a crucial role in guiding this bi-stability, while non-orientability enhances the robustness of these states, isolating them within specific regions of parameter space. We conclude with an analytical treatment of the model through a continuum description and experimental validation, demonstrating the rich physics of these systems in out-of-equilibrium conditions. This research highlights the potential of frustrated active metamaterials in guiding non-reciprocal dynamics and designing controllable multi-stable systems