Quasi-periodic sonic black hole with low-frequency acoustic and elastic bandgaps

• Published in: Composite structures 2024-06, Vol.337, p.118046, Article 118046
• Main Authors: Sheng, Hui, He, Meng-Xin, Pueh Lee, Heow, Ding, Qian
• Format: Article
• Language: English
• Subjects: Acoustic bandgap; Elastic bandgap; Sonic black hole
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2024.118046

Metamaterials with the capability to control wave propagation in fluid or solid mediums have attracted plenty of fundamental scientific and engineering research in recent decades. This paper proposes a novel metamaterial, named Quasi-periodic sonic black hole (Q-SBH), to achieve both acoustic bandgap and elastic bandgap. The Q-SHB consists of two functional units: outer soft shells and inner stiff rings. The stiff rings with decaying inner radii are connected by soft shells, and the distances between rings take linear variation. The Q-SBH reserves the slow-sound effect of sonic black hole and the non-uniformly distributed rings serve as mistuning vibration absorbers. On the basis of these characteristics, broadband low-frequency acoustic and elastic bandgaps are generated simultaneously. We demonstrate the attenuation performance of the Q-SBH by theoretical, numerical and experimental methods. Parametric analysis and multi-objective optimization of the structure are carried out. The results demonstrate the great potential of the proposed Q-SBH in a broad range of physical fields requiring both air-borne noise reduction and structural vibration suppression.