Gradient zigzag metamaterial beams as broadband vibration isolators for beam-like structures

TL;DR

This paper introduces gradient zigzag metamaterial beams with broad flat bands that serve as effective broadband vibration isolators for beam-like structures, overcoming the narrow stop-band limitations of traditional phononic crystals.

Contribution

The study proposes a novel gradient zigzag metamaterial beam design with flat bands over a broad frequency range, verified through numerical simulations and experiments, offering a new approach for broadband vibration isolation.

Findings

Flat bands are caused by local resonance in the gradient zigzag structure.

The metamaterial beams effectively trap elastic waves at flat band frequencies.

Experimental results confirm the vibration isolation performance.

Abstract

Phononic crystals (PCs) and metamaterials are artificially structured materials with the unprecedented property of the existence of complete stop-bands. However, the generally narrow width of the stop-bands in such materials severely limits their applicability. Here, a particular kind of gradient zigzag metamaterial beams exclusively with flat bands within a broad frequency range is proposed based upon our previously proposed uniform counterparts. The calculated band structures by the Finite Element Method (FEM) and the Spectral Element Method (SEM) show the distinctly different characteristics of the gradient zigzag metamaterial beams from the conventional PCs and metamaterials, where the band structures are totally filled with flat bands within a broad frequency range without the normal pass bands. These flat bands are caused by the local resonance of certain parts in the gradient zigzag metamaterial beams, and the elastic waves with the frequencies at these flat bands are trapped in the resonant parts and cannot propagate. As a result, our proposed gradient zigzag metamaterial beams can be used as broadband vibration isolators for beam-like structures, which is verified by both numerical simulations and experiments conducted on the 3D-printed samples. This design strategy opens a new avenue for designing and constructing novel broadband vibration isolators.