Sound insulation properties of membrane-type acoustic metamaterials with petal-like split rings

Abstract

Membrane-type acoustic metamaterials (MAMs) are lightweight and flimsy materials with excellent low-frequency insulation performance, which breaks the limitations of the traditional mass law and provides a new idea for noise reduction in the low-frequency range. To further broaden the sound insulation bandwidth on the premise of lightweight design, a novel MAM with petal-like rings is proposed, and the parametric studies on the structural parameters of split rings are carried out in this paper. By combining the finite element model simulation and impedance tube test, the effectiveness of the proposed structure and the correctness of the numerical simulation are validated. Moreover, the sound transmission loss curves and modal shapes of four different structures are computed and analyzed to clarify the insulation mechanism of the novel structure. Finally, the width, the center angle, the centroid position, and the weight of the split rings in the novel structure are parametrically analyzed to figure out the regulation rules of the sound insulation characteristics.

Acoustic Insulation Mechanism of Membrane-Type Acoustic Metamaterials Loaded with Arbitrarily Shaped Mass Blocks of Variable Surface Density

“…It is easy to see from Figure 11a that, when the mass block was placed eccentrically, its STL curve was shifted, but the magnitude of the main peaks and valleys (the peaks and valleys produced when the mass is coincident with the film center of mass) and the frequency bands generated did not change much; when the mass block was placed too close to the film boundary, its STL was significantly shifted. Whereas this differs from the behavior of the cylindrical mass block, which produces more peaks and valleys when eccentric [7][8][9][12][13][14][15][16][17][18][19][20], these additional sound insulation summits affected the frequency band and size of the main peaks. It was shown that the hexagonal cone mass block had a more stable sound insulation effect in the lower frequency band.…”

“…Guancong Ma et al [6] established a membrane-type metamaterial structure with cavities to increase the noise reduction effect of the structure by using hybrid resonance. Huang et al [7] proposed a petal-shaped circular membrane-type metamaterial that is lighter than the cylindrical structure while ensuring certain STL effect. Lu et al [8] Materials 2022, 15, 1556 2 of 16 investigated the STL in the eccentric state of the mass block and introduced a preparation technique to accurately apply tension to the film.…”

Acoustic Insulation Characteristics and Optimal Design of Membrane-Type Metamaterials Loaded with Asymmetric Mass Blocks

“…Zhou et al [ 23 ] designed a symmetrical cross-shaped mass block structure that is easy to achieve dynamic balance according to the low-order vibration characteristics and realized multi-state continuous sound insulation peaks. On the basis of Zhou’s model, Huang et al [ 24 ] proposed a new MAM with petal-like rings, which achieved a similar sound insulation effect under lighter mass conditions. Lu et al [ 25 ] designed a mass block in the form of split rings, which can obtain better acoustic performance through optimization of the distribution of eccentric masses.…”

Effect of geometrical parameters and additional mass on the acoustic and vibration control of the bilayer resonant metamaterials

“…Membrane-type structures are an important type of local resonant acoustic metamaterials with the advantages of lightweight, small size, and high pertinence, [14][15][16] which are widely used in the field of low-frequency sound insulation. Membrane resonators achieve acoustic effects similar to those of Helmholtz resonators through a different mechanism.…”