Contribution
Influence of damping layers in locally resonant acoustic metameterials on sound barrier performance
* Presenting author
Abstract:
Sound barriers typically utilize absorber materials like mineral wool, which are challenging to recycle. Acoustic metamaterials – so-called locally resonant acoustic metamaterials (LRAM) - offer a new possibility to reduce vibration and noise while being more accessible to recycle. Compared to classical absorber materials, where the wave's energy is dissipated via boundary layers, LRAMs are based on mechanical resonators that act as absorbers of mechanical energy. In the case of locally resonant structures, the wave's energy does not have to be dissipated per se, as long as the vibration does not contribute to acoustic emissions. In this contribution, however, we investigate the influence of an additional damping layer within an LRAM unit cell on the mechanical and acoustic behavior of a sound barrier element. The locally resonant structures are similar and spaced equidistantly on the base plate for easier manufacturing. A parameter study is set up to investigate the influence of such a damping layer on the absorption- and reflection coefficient as well as sound transmission using finite element simulations. Based on the desired stopband, an optimum concerning sound absorption and width of the stopband can be found.