Elmadih Waiel, Chronopoulos Dimitrios, Zhu Jian
Institute for Aerospace Technology & The Composites Group, University of Nottingham, Nottingham, NG8 1BB, UK.
Metamaterials Ltd, Wallington, SM6 0TL, Surrey, UK.
Sci Rep. 2021 Jul 19;11(1):14635. doi: 10.1038/s41598-021-94053-3.
In this work, we present a single low-profile metamaterial that provides bandgaps of acoustic and elastic waves at the same time. This was done by ensuring impedance mismatch in two different domains, the fluid domain where the acoustic waves propagate and the solid domain where the elastic waves propagate. Through creatively designing the metamaterial, waves of certain nature and frequencies of interest were completely blocked in the solid and fluid domains simultaneously. The simulation results showed bandgaps with acoustic waves attenuation below 5 kHz and elastic waves attenuation below 10 kHz. The acoustic and elastic dispersion curves of the metamaterials were calculated for various designs with various diameters and neck lengths, and the bandgaps were calculated. These parameters can be used as means for tuning both the acoustic and elastic bandgaps. A representative design of the metamaterial was manufactured on a laser powder bed fusion system and the dynamic performance was measured at various points. The measurements were carried out using a dynamic shaker setup and the dynamic performance was in good agreement with the numerical modelling results. Such metamaterials can be used for simultaneous acoustic and elastic attenuation, as well as saving in space and material consumption, in various fields including building construction, automobile, aerospace and rocket design.
在这项工作中，我们展示了一种单一的低剖面超材料，它能同时提供声波和弹性波的带隙。这是通过确保在两个不同区域（声波传播的流体区域和弹性波传播的固体区域）的阻抗失配来实现的。通过创造性地设计这种超材料，特定性质和感兴趣频率的波在固体和流体区域同时被完全阻挡。模拟结果显示，在低于5kHz时存在声波衰减带隙，在低于10kHz时存在弹性波衰减带隙。针对具有不同直径和颈部长度的各种设计，计算了超材料的声学和弹性色散曲线，并计算了带隙。这些参数可作为调节声学和弹性带隙的手段。在激光粉末床熔融系统上制造了这种超材料的一个代表性设计，并在各个点测量了其动态性能。测量是使用动态振动台装置进行的，动态性能与数值模拟结果吻合良好。这种超材料可用于建筑施工、汽车、航空航天和火箭设计等各个领域的同时声学和弹性衰减，以及节省空间和材料消耗。
