Experiments on unidirectional excitation of designer flexural edge waves

Abstract

We demonstrate the unidirectional propagation of structure-induced edge waves in a thin plate. These waves, termed designer flexural edge waves (DFEWs), are observed along the free edge of a thin plate featuring periodically corrugated rectangular grooves. These DFEWs can be activated unidirectionally using either a pair of point sources exhibiting phase differences or a “chiral” source characterized by a clockwise phase distribution, as evidenced in the experimental results. The observed asymmetric behavior in the former scenario is attributed to the destructive interference among the edge waves. In the latter scenario, we elucidate this phenomenon by analyzing the spatial Fourier spectrum. The chiral source induces a spatial asymmetry, while the periodic edge structure selects the specific evanescent components of the asymmetric Fourier spectrum.