Acoustic metamaterials can be realised by the periodic distribution of features that vary from rigid inclusions and discontinuous cuts to sub-wavelength resonators. The use of lightweight elements in the resonator design gave rise to membrane-type acoustic metamaterials (MAMs), which exhibit relevant attenuation on a narrow frequency range. The use of smart materials, resulting in smart MAMs, paves the way towards tunable systems that can improve the attenuation performance at different frequency ranges. This work presents a numerical and experimental investigation on the use of smart MAMs for addressing unidirectional acoustic perturbation through the combination of a prestressed membrane with shunted piezoelectric elements. A concept unit cell has been modelled using fully coupled electro-vibroacoustic finite elements and verified experimentally in an impedance tube, adapted for sound transmission loss (STL) measurements. Then, a novel acoustic metamaterial is proposed by arranging a number of the proposed unit cells along the wave propagation direction. Numerical exercises, based on the validated unit cell model, show the formation of an electroelastic attenuation band around the first open-circuit membrane mode. The smart MAM is capable of delivering large STL, not only at the membrane anti-resonance, as expected, but also at a band around the first resonance frequency, showing a promising application for an effective, lightweight acoustic barrier.

声学超材料可以通过特征的周期性分布来实现，这些特征从刚性夹杂物和不连续切割到亚波长谐振器。在谐振器设计中使用轻质元件产生了膜式声学超材料 (MAM)，它在较窄的频率范围内表现出相关的衰减。智能材料的使用，产生了智能 MAM，为可调谐系统铺平了道路，该系统可以改善不同频率范围内的衰减性能。这项工作对使用智能 MAM 通过预应力膜与并联压电元件的组合解决单向声扰动进行了数值和实验研究。使用完全耦合的电振动声有限元对概念单元进行建模，并在阻抗管中进行了实验验证，适用于声音传输损耗 (STL) 测量。然后，通过沿波传播方向排列许多提出的单位单元，提出了一种新的声学超材料。基于经过验证的晶胞模型的数值练习表明，在第一个开路膜模式周围形成了一个电弹性衰减带。智能 MAM 能够提供大的 STL，不仅在膜反共振方面，如预期的那样，而且在第一共振频率附近的频带上，显示出有效、轻量级声屏障的有前途的应用。通过沿波传播方向排列许多提出的单位单元，提出了一种新的声学超材料。基于经过验证的晶胞模型的数值练习表明，在第一个开路膜模式周围形成了一个电弹性衰减带。智能 MAM 能够提供大的 STL，不仅在膜反共振方面，如预期的那样，而且在第一共振频率附近的频带上，显示出有效、轻量级声屏障的有前途的应用。通过沿波传播方向排列许多提出的单位单元，提出了一种新的声学超材料。基于经过验证的晶胞模型的数值练习表明，在第一个开路膜模式周围形成了一个电弹性衰减带。智能 MAM 能够提供大的 STL，不仅在膜反共振方面，如预期的那样，而且在第一共振频率附近的频带上，显示出有效、轻量级声屏障的有前途的应用。