Nonlinear waves at the free surface of flexible mechanical metamaterials

TL;DR

This paper explores how nonlinear pulses propagate along the free surface of flexible mechanical metamaterials, revealing stable surface wave behavior and providing design guidelines to optimize their stability by reducing interactions with linear surface modes.

Contribution

It demonstrates the existence and stability of nonlinear surface pulses in flexible metamaterials and offers geometric guidelines to enhance their stability by minimizing dispersive interactions.

Findings

Surface nonlinear pulses are stable and can propagate along the free surface.

Stability improves when surface pulses minimally interact with linear surface modes.

Guidelines for geometry design to reduce dispersive interactions.

Abstract

In this letter we investigate the propagation of nonlinear pulses along the free surface of flexible metamaterials based on the rotating squares mechanism. While these metamaterials have previously been shown to support the propagation of elastic vector solitons through their bulk, here we demonstrate that they can also support the stable propagation of nonlinear pulses along their free surface. Further, we show that the stability of these surface pulses is higher when they minimally interact with the linear dispersive surface modes. Finally, we provide guidelines to select geometries that minimize such interactions.