Poster: Macroscopic model of phononic effects in acoustic metamaterials (AMM).

AMM represent a novel type of materials, assembled of a network of particles, mimicking the structure of solid state crystals. Like crystals, AMM’s possess unusual physical properties emerging from collective interaction of their constituent particles, with numerous applications in electronics and signal processing: filters, directional splitters and couplers, diodes, etc. Developing an actual AMM structure is a long and costly task. To speed up the process, we suggest building macroscopic physical models of the AMM’s. We start with one-dimensional tube setup from Teachspin, Inc. When the excitation frequency is sufficiently high the closely-separated tube resonances overlap, thus forming a continuous wave propagation spectrum. Partitioning the tube with periodically spaced identical irises creates allowed and prohibited for propagation frequency bands, similar to the band gaps in a solid dielectric. Adjusting the aperture diameter of the irises, we can control the bangaps. Replacing just one of the irises, or changing the distance between two of the neighboring irises, we can introduce a defect where a localized oscillation can dwell. Currently we are working on a two-dimensional structure which will allow us not only to filter out the sound of certain frequencies, but to change propagation direction of the waves according to their frequencies. Our work will also be interesting for students studying acoustics, solid state and materials physics.