Highly efficient acoustic absorber designed by backing cavity-like and filled-microperforated plate-like structure

Crowded living conditions and increasingly severe noise problems necessitate the development of a low-thickness sound absorption material with remarkable sound absorption performance. Here, simple materials such as sodium alginate aerogel (SA) and polyurethane (PU) foam are used to combine with special 3D spacer fabric to design an innovative highly-efficient acoustic absorber composite (B&M−L composite). It integrates a "backing cavity-like" (BC-L) structure and "filled-microperforated plate-like" (MPP-L) structure. Thereby, it realizes porous and resonant sound absorption at a small thickness. The superior structure design combining strong resonance with porous structure endows the new type of composite with a remarkable absorption performance. Specifically, the peak absorption coefficient is 0.98, the average absorption coefficient at a thickness of 10 mm is 0.71, and the noise reduction coefficient per unit thickness of B&M−L composites exceeds those of most of the reported sound absorption materials. Based on its remarkable acoustic performance, good mechanical properties, heat insulation performance, and thermal stability, the B&M−L composite provides a convenient and inexpensive method to improve the overall performance of porous sound absorption materials, and displays significant potential for use in the fields of construction, transportation, and large mechanical equipment.