A Comparative Study and Analysis of Layered-Beam and Single-Beam Metamaterial Structures: Transmissibility Bandgap Development

Recently, layered-beam metamaterial structures have been gaining popularity in a variety of engineering applications including energy harvesting and vibration isolation. While both single-beam metamaterial structures and layered-beam metamaterial structures are capable of generating bandgaps, it is important to understand the limitations of each type of metamaterial structure in order to make informed design decisions. In this article, a comparative study of bandgap development in single-beam metamaterial structures and layered-beam metamaterial structures is presented. The results show that for the single-beam metamaterial structure, with equally spaced local resonator designs, only one significant bandgap is developed at approximately 300–415 Hz. This bandgap occurs near the resonant frequency of the local resonators, i.e., 309 Hz. The results also show that when the spacing and the design of the local resonators are desired to remain fixed, layering the horizontal beams offers a significant pathway for both lowering the bandgap and developing additional bandgaps. The double-layered beam-type metamaterial structure studied in this work generates two bandgaps at approximately 238–275 Hz and 298–410 Hz. When the goal is to keep the number of local resonators per beam constant, increasing the length of the unit cells offers an alternative technique for lowering the bandgaps.