Control of edge modes in finite vibro-acoustic resonant metamaterials

Metamaterials have shown great potential as lightweight and performant vibro-acoustic solutions. Made from conventional materials, metamaterials exhibit stop band behavior resulting from the dynamic interaction between a host structure and its resonant additions on a subwavelength scale. In these stop bands, metamaterials outperform common vibro-acoustic solutions, beating the mass law. Stop band behavior can be predicted in the design stage with unit cell modeling, assuming the metamaterial to be an infinite periodic structure. In any practical application, structures have a finite size and their dynamic behavior is influenced by the boundary conditions. This paper analyzes numerically and experimentally the interaction of a 1D finite sized metamaterial with different boundary conditions. The effect of the edge modes on the predicted stop band behavior is investigated. Two methods are proposed to reduce the influence of edge modes and to achieve the designed stop band behavior performance also in the finite metamaterial system.