Phononic crystals and metamaterials are arrangements of basic building blocks that repeat in space. These materials can allow for frequency dependent control of acoustic and elastic waves.&nbsp;&nbsp;Such frequency-dependent behavior opens up the opportunity for designing advanced materials with peculiar dynamical characteristics that can be utilized for a wide range of applications such as noise and vibrations isolation, wave filtering, impact mitigation, and acoustic cloaking [1-2].&nbsp;&nbsp;Recent metamaterials have been proposed for the control of waves based on amplitude and direction in addition to their frequency&nbsp;[3-5]. Such amplitude dependent behavior usually involves harnessing nonlinear elements, where only a wave with an amplitude above a certain threshold can be transmitted through the media. Non-reciprocity, on the other hand, where a wave propagates through the medium if excited from one end, but not the other, can be achieved through bi-stable potentials, for example. In bi-stable or multi-stable metamaterial, nonreciprocity has been theoretically proposed and experimentally observed, however in many instances, the metamaterials lacked the ability to be reset or reverse direction in a quick and simple manner. Here, we realize a metamaterial based on repulsive magnetic unit cells [6] with built in bi-stable potentials. Our metamaterials are designed to filter waves in a direction dependent fashion. For example, a wave excited from the left end, but not the right end is allowed to pass. This directionality can be tuned, and rest based on an external control parameter. We analyze these metamaterials analytically, numerically and experimentally.&nbsp;[1] Maldovan, Martin. "Sound and heat revolutions in phononics." Nature 503, no. 7475 (2013): 209-217.&nbsp;[2] Hussein, Mahmoud I., Michael J. Leamy, and Massimo Ruzzene. "Dynamics of phononic materials and structures: Historical origins, recent progress, and future outlook." Applied Mechanics Reviews 66, no. 4 (2014).&nbsp;[3] Kochmann, Dennis M., and Katia Bertoldi. "Exploiting microstructural instabilities in solids and structures: from metamaterials to structural transitions."&nbsp;Applied mechanics reviews&nbsp;69, no. 5 (2017).&nbsp;[4] Nassar, Hussein, Behrooz Yousefzadeh, Romain Fleury, Massimo Ruzzene, Andrea Alù, Chiara Daraio, Andrew N. Norris, Guoliang Huang, and Michael R. Haberman. "Nonreciprocity in acoustic and elastic materials." Nature Reviews Materials 5, no. 9 (2020): 667-685.&nbsp;[5] Bilal, Osama R., André Foehr, and Chiara Daraio. "Bistable metamaterial for switching and cascading elastic vibrations." Proceedings of the National Academy of Sciences 114, no. 18 (2017): 4603- 4606.&nbsp;[6] A. A. Watkins and O. R. Bilal, “Demultiplexing Infrasound Phonons with Tunable Magnetic Lattices” Frontiers in Materials7, 410 (2020).

Re-Programmable Non-Reciprocal Wave Transmission in Nonlinear Magnetic Lattices

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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