Modeling of 3-D printed membrane-type acoustic metamaterial unit cells and investigating the dynamic behaviors

Abstract

The manipulation of low- and mid-frequency sounds using artificially engineered structures has gathered significant research interest as a promising approach to mitigate noise. With this intention, the investigation of acoustic metamaterials has emerged as a considerable field. These particular structural forms possess exceptional qualities and hold the potential for further progress. Specifically, membrane-type acoustic metamaterials (M-AMMs) have gathered interest due to their ability to yield desired sound insulation properties through the local resonance mechanism of a mass-spring system. This resonance phenomenon can be tuned within the aforementioned frequency range, offering a viable solution for achieving enhanced sound attenuation. So far, there have been several efforts to design and simulate such structures using conventional hand-made techniques. However, to minimize the challenges arising from manufacturing and to ensure consistent results, it is worth investigating the possibility of creating these unit cells through additive fabrication approaches. In order to investigate the dynamic behavior of M-AMM unit cells manufactured by a multi-material printing approach, finite element analyses are conducted in Ansys® Workbench. As a primary point, the pre-stress in the membrane induced by a secondary structure is realized and investigated. The effect of printed mass configurations and pre-stress of the membrane are analyzed via different modeling approaches. Whereas the magnitude of the mass remains equal for all mass-attached unit cells, the shape and distribution are varied. The outputs from the simulations and results obtained from the experiment are compared and discussed with respect to further investigations to realize M-AMMs.