Locally Resonant Materials for Energy Harvesting at Small Scale

Energy Localization through Locally Resonant Materials

“…This system, which is similar to a Fabry-Pérot interferometer in optics [26], will be referred to as Resonant Energy Harvester (REH). A similar configuration has been already studied by the authors in [19], although now the two barriers are made of a ternary LRM instead of the binary heterogeneous material previously employed. The LRM is composed of a two dimensional periodic repetition of the square unit cell represented in Figure 2, with a stiff matrix Y m containing an almost rigid circular fiber Y f , coated by a very compliant layer Y c .…”

“…This system, which is similar to a Fabry-Pérot interferometer in optics [ 26 ], will be referred to as Resonant Energy Harvester (REH). A similar configuration has been already studied by the authors in [ 19 ], although now the two barriers are made of a ternary LRM instead of the binary heterogeneous material previously employed.…”

“…Considering a propagating input wave, the integration constants are obtained imposing the continuity of the displacement and of the stress between the various regions and the conditions at infinite. In particular, when considering an incoming wave which travels from the left toward the right (see Figure 3 ) of amplitude 1, the displacement in the different parts reads (see [ 19 ] for details): where and are respectively the amplitudes of the reflected and transmitted wave: with …”

“…Beside extending the analytic results obtained in [19] for a REH with binary LRM to the case of a REH with three components LRM, the paper provides a new numerical validation, introduces the concept of indexes of concentration and develops maps of these indexes at varying frequency and geometry of the REH. The maps can be of practical use in the design of a real REH that, with a fixed geometry, should work in a wide range of frequencies.…”

“…In the present work we explore the possibility to couple the advantage of the LRM mechanism to create band gaps at low frequencies with the energy localization mechanism in local defects of regular lattices to design and optimize a Resonant Energy Harvester (REH). An initial attempt in this direction was presented in [19], considering binary LRMs. The ternary LRM here considered, endowed with two-dimensional periodicity, is constituted by a stiff matrix with almost rigid cylindrical inclusions coated by a compliant material.…”