Manipulating Mechanical Waves Using Programmable Periodic Structures

Abstract

Mechanical metamaterials have been extensively explored due to their extraordinary properties that allow vibration and acoustic attenuation as well as wave manipulation. The metamaterial term is nowadays employed to designate rationally designed and tailored periodic artificial materials with physical characteristics not found in nature. The presence of a band gap, a frequency range in which vibration disturbances will not propagate through the structure, is a key feature of metamaterials. Band gaps pave the way to create acoustic and vibration barriers at low frequency, seismic shielding, acoustic diode, two-dimensional waveguides and topological insulators. Usually, periodic structures present fixed dynamic behavior after the unit cell designing. Hence, their working frequency range or even their functionality would be only modified with a new design and a new structure fabrication. The periodic structures capabilities could be expressively expanded by tailoring or by reconfiguring the unit cell properties, resulting in tunable band gaps and hence, programmable phononic crystals and metamaterials. Programmable periodic structures can reveals extraordinary potentialities and versatility that cannot be achieved by their passive counterparts. Therefore, this research project aims to investigate smart and programmable phononic crystals and metamaterials to attenuate sound and vibration as well as to manipulate mechanical waves in a more efficient and versatile way. The wave propagation in periodic structures is a rich and dynamic research area with a wide range of open topics that have high potential to solve old engineering problems, to create new technologies and to impact our every-day-life.