Abstract
Membrane-type acoustic metamaterial (MAM) has exhibited superior sound isolation properties, as well as thin and light characteristics. However, the anti-resonance modes of traditional MAMs are generated intermittently in a wide frequency range causing discontinuities in the anti-resonance modes. Achieving broadband low-frequency sound attenuation with lightweight MAM design is still a pivotal research aspect. Here, we present a strategy to realize wide sound-attenuation bands in low frequency range by introducing the design concept of bionic configuration philosophy into the MAM structures. Built by a polymeric membrane and a set of resonators, two kinds of MAM models are proposed based on the insight of a spider web topology. The sound attenuation performance and physical mechanisms are numerically and experimentally investigated. Multi-state anti-resonance modes, induced by the coupling of the bio-inspired arrangement and the host polymer film, are systematically explored. Significant sound attenuation is numerically and experimentally observed in both the lightweight bio-inspired designs. Remarkably, compared with a traditional MAM configuration, a prominent enhancement in both attenuation bandwidth and weight-reduction performance is verified. In particular, the bio-inspired MAM Model I exhibits a similar isolation performance as the reference model, but the weight is reduced by nearly half. The bio-inspired Model II broadens the sound attenuation bandwidth greatly; meanwhile, it retains a lighter weight design. The proposed bio-inspired strategies provide potential ways for designing sound isolation devices with both high functional and lightweight performance.
Highlights
Ever-increasing requirements and higher demands for noise and vibration suppression have attracted abundant effort to design novel structures and materials that are lightweight, yet with exceptional sound isolation/attenuation performance
The concept of acoustic metamaterials has opened a new route to lowfrequency noise isolation with compact and lightweight structures, which can realize unique bandgap effects for effectively blocking wave propagation at the corresponding frequencies based on locally resonant behaviors [5,6,7]
The experimentally measured sound transmission loss (STL) peaks are slightly less than the numerical results, which is mainly induced by the manufacturing accuracy and ignoring the damping effect in numerical models
Summary
Ever-increasing requirements and higher demands for noise and vibration suppression have attracted abundant effort to design novel structures and materials that are lightweight, yet with exceptional sound isolation/attenuation performance. The concept of acoustic metamaterials has opened a new route to lowfrequency noise isolation with compact and lightweight structures, which can realize unique bandgap effects for effectively blocking wave propagation at the corresponding frequencies based on locally resonant behaviors [5,6,7]. Such artificial structures have realized a flurry of abnormal dynamic properties, including single/double negative/zero mass-density or modulus etc. A rich variety of extraordinary acoustic wave manipulations, such as negative refraction [13,16], acoustic cloaking [16], unidirectional transmission [17] and so forth, have been enabled by such an innovative design philosophy
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