Abstract

Co Authors: Timothy A. Starkey, Daniel B. Moore, Ian R. Hooper, J. R. Sambles, Alastair P. Hibbins Abstract:  Engineering the dispersion of acoustic or elastic waves using coupling terms that spatially reach beyond the immediate local environment, or unit cell, is an ‘emerging topic’ in metamaterial design. In this talk, we present the background and motivations of this ‘new trend’ along with experimental studies in acoustic and elastic systems that realise beyond-nearest-neighbour coupling to introduce dispersion relations with extrema within the first Brillouin zone. In acoustics, we use mixed waveguide-surface wave coupling, whilst in elastics we develop an elastic scaffold (with a recognisable popular British construction kit), with reconfigurable coupling elements and demonstrate the effects of structural symmetries on these exotic dispersion relations.