Trapped Modes and Negative Refraction in a Locally Resonant Metamaterial: Transient Insights into Manufacturing Bounds for Ultrasonic Applications

The transient scattering of in-plane elastic waves from a finite-sized periodic structure, comprising regular grid Swiss-cross holes arranged according to square lattice, is considered. theoretical and numerical modelling focuses on the unexplored ultrasonic frequency regime, well beyond first, wide, locally resonant band-gap structure. Dispersive properties array, determined by Bloch–Floquet analysis, are used identify candidates for high-fidelity GPU-accelerated simulations. Several unusual wave phenomena identified simulations, including negative refraction, focusing, partial cloaking, trapping. finite element framework offers insights lifetimes such potential practical applications. In addition, nonideal counterparts with rough edges modelled using characteristic statistical parameters commonly observed in additive manufacturing. analysis shows that effects appear likely be robust respect manufacturing uncertainties future studies.