Acoustic propagation through a duct metamaterial attached with periodic multi-resonant cavities

Presently, noise pollution in ducts is considered seriously, and numerous studies concerning sound absorption in pipes are ongoing globally. Aiming at the difficulty to eliminate the low-frequency noise in pipeline, a multi-resonant cavity duct metamaterial is proposed. The acoustic properties of the metamaterial are calculated using the energy method based on the Hamilton principle and the transfer matrix methodology. The result demonstrates that the duct metamaterial, due to its band gaps and negative bulk modulus, obtains several sound absorption peaks and is advantageous to sound elimination in low frequency. The good acoustic characteristics of the duct metamaterial for sound insulation can be attributed to the plate-cavity interaction. Parametric analysis of the proposed structure is also carried out. This study demonstrates the application prospects of duct metamaterials for multi-frequency sound absorption in engineering practice.