Rising Above Uncertainties: An Experimental Investigation on Adaptive Waveguiding Using Locally Resonant Piezoelectric Metasurface

Adaptive metasurfaces composed of tunable, locally resonant piezoelectric unit cells offer configurable dispersive properties, thereby facilitating the formation of phase gradients for wavefront redirection or transmission barriers for vibration suppression. Nevertheless, full-scale physical demonstrations remain an elusive challenge. There exists complicated electromechanical coupling of response variables with respective operational ranges that are limited in physical implementation, which is further compounded by inevitable local variations in piezoelectric transducer circuitry properties. The present article provides a comprehensive experimental investigation on a locally resonant piezoelectric metasurface, composed of a 10 by 5 array of unit cells shunted with tunable analog synthetic inductors. We start from an analytical wave dispersion model to outline the design process, which is verified through finite-element analysis. Two experimental case studies are then presented with mechatronic synthesis details. With careful tuning, we successfully demonstrate the anomalous refraction of elastic waves as well as the transmission bandgaps. To understand how local variations impact waveguiding, uncertainty quantification and sensitivity analyses are carried out and correlated with experimental findings. By delineating how the variations influence the realized refraction angle and transmission bandgap characteristics, we develop a foundational understanding for the performance of such systems in implementation.