Dial-in Topological Metamaterials Based on Bistable Stewart Platform

TL;DR

This paper introduces a tunable topological metamaterial based on bistable Stewart platforms that can guide mechanical waves robustly and switch wave paths in situ without active materials.

Contribution

It presents a novel topological metamaterial system utilizing bistability in Stewart platforms for in situ tuning of waveguides, inspired by the quantum valley Hall effect.

Findings

Topological waveguides support robust, backscattering-immune, one-way wave propagation.

The system can switch between topological and traditional waveguides.

Tuning is achieved simply by a dial-in action without active materials.

Abstract

Recently, there have been significant efforts to guide mechanical energy in structures by relying on a novel topological framework popularized by the discovery of topological insulators. Here, we propose a topological metamaterial system based on the design of the Stewart Platform, which can not only guide mechanical waves robustly in a desired path, but also can be tuned in situ to change this wave path at will. Without resorting to any active materials, the current system harnesses bistablilty in its unit cells, such that tuning can be performed simply by a dial-in action. Consequently, a topological transition mechanism inspired by the quantum valley Hall effect can be achieved. We show the possibility of tuning in a variety of topological and traditional waveguides in the same system, and numerically investigate key qualitative and quantitative differences between them. We observe that even though both types of waveguides can lead to significant wave transmission for a certain frequency range, topological waveguides are distinctive as they support robust, back scattering immune, one-way wave propagation.