In this work we experimentally achieve 1 kHz-wide directional band-gaps for elastic waves spanning a frequency range from approximately 8 to 11 kHz. One-way propagation is induced by way of a periodic waveguide consisting in an aluminum beam partially covered by a tightly packed array of piezoelectric patches. The latter are connected to shunt circuits and switches which allow for a periodic modulation in time of the cell properties. A traveling stiffness profile is obtained by opportunely phasing the temporal modulation of each active element, mimicking the propagation of a plane wave along the material, therefore establishing unidirectional wave propagation at bandgap frequencies.
@article{arxiv.1909.13224,
title = {Experimental observation of non-reciprocal band-gaps in a space-time modulated beam using a shunted piezoelectric array},
author = {Jacopo Marconi and Emanuele Riva and Matteo Di Ronco and Gabriele Cazzulani and Francesco Braghin and Massimo Ruzzene},
journal= {arXiv preprint arXiv:1909.13224},
year = {2020}
}