Dynamic cloaking of a diamond-shaped hole in elastic plate

TL;DR

This paper demonstrates a practical unidirectional invisibility cloak for flexural waves in elastic plates, effectively hiding a diamond-shaped hole for pulsed waves through area-preserving transformations and experimental validation.

Contribution

It introduces a novel cloak design for elastic waves that maintains invisibility for short pulses, supported by time-resolved experiments and 3D simulations.

Findings

Pulsed plane waves are deviated by the cloak, but wavefronts recombine behind it.

The cloak effectively renders the hole invisible for short pulses.

Experimental results align with full-elasticity simulations.

Abstract

Invisibility cloaks for flexural waves have been mostly examined in the continuous-wave regime, while invisibility is likely to deteriorate for short pulses. Here, we propose the practical realization of a unidirectional invisibility cloak for flexural waves based on an area-preserving coordinate transformation. Time-resolved experiments reveal how the invisibility cloak deviates a pulsed plane-wave from its initial trajectory, and how the initial wavefront perfectly recombines behind the cloak, leaving the diamond-shaped hole invisible, notwithstanding the appearance of a forerunner. Three-dimensional full-elasticity simulations support our experimental observations.