3D rainbow phononic crystals for extended vibration attenuation bands

Abstract

We hereby report for the first time on the design, manufacturing and testing of a three-dimensional (3D) nearly-periodic, locally resonant phononic crystal (PnC). Most of the research effort on PnCs and metamaterials has been focused on the enhanced dynamic properties arising from their periodic design. Lately, additive manufacturing techniques have made a number of designs with intrinsically complex geometries feasible to produce. These recent developments have led to innovative solutions for broadband vibration attenuation, with a multitude of potential engineering applications. The recently introduced concept of rainbow metamaterials and PnCs has shown a significant potential for further expanding the spectrum of vibration attenuation in such structures by introducing a gradient profile for the considered unit cells. Given the above, it is expected that designing non-periodic PnCs will attract significant attention from scientists and engineers in the years to come. The proposed nearly-periodic design is based on cuboid blocks connected by curved beams, with internal voids in the blocks being implemented to adjust the local masses and generate a 3D rainbow PnC. Results show that the proposed approach can produce lightweight PnCs of a simple, manufacturable design exhibiting attenuation bandwidths more than two times larger than the equivalent periodic designs of equal mass.

Potentiale additiv gefertigter Gitterstrukturen – ein Review

“…Dabei steht meist im Fokus möglichst gute Vibrationsdämpfungseigenschaften zu erzeugen, etwa durch speziell entwickelte Zellen [12,30]. Des Weiteren werden Zellen dahingehend ausgewählt und ausgelegt, dass sie möglichst große Bandbreiten an Schwingungen dämpfen, u. a. durch resonante Phononische Kristalle (PnC) [31] und Topologieoptimierung von Gitterstrukturen [32]. Eine weitere Möglichkeit, die Schwingungsabsorptionseigenschaften zu verbessern, sind eine gezielte Auslegung auf die Absorption von Eigenfrequenzen im System [33] und das Verschieben der Struktur-Eigenfrequenz in einen möglichst hohen Frequenzbereich [34,35].…”

Nature-inspired designs for disordered acoustic bandgap materials

“…A number of recent studies on mechanical metamaterials [1][2][3][4][5][6][7][8][9][10] with full acoustic bandgaps have attracted intense interests. These materials provide opportunities to precisely control propagations of mechanical waves and have a broad range of potential applications in vibration isolation, 11 acoustic cloaking, 12 wave filters, 13,14 waveguides 15,16 and mechanical switches.…”

Broadband Vibration Attenuation Achieved by 2D Elasto-Acoustic Metamaterial Plates with Rainbow Stepped Resonators

“…Beli et al [54] proved that the spatial correlated variability could lead to widened bandgaps for cantilever-in-mass metamaterials. Meng et al [55][56][57][58][59] investigated rainbow metamaterial beams with spatially varying oscillators and rainbow phononic crystal lattices with spatial varying mass blocks and found that the rainbow structures could generate broader bandgaps compared with periodic ones.…”