An Acoustic Coating with Cylindrical Cavities Embedded in the Diagonal Direction of an Elastic Medium with Broadband Sound Absorption Performance

Acoustic structures with cavities are generally applied in underwater acoustic coatings. Previous studies on improving the sound absorption bandwidth of anechoic coatings with cavities have generally focused on increasing the number of cavity layers, resulting in a large total thickness. An acoustic model composed of cylindrical cavities distributed in the diagonal direction of a soft elastic medium is presented in this study to solve this puzzle. The distances between cavities are designed as negative gradient so as to obtain a broadband absorption bandwidth. Compared with the acoustic model with cavities distributed in the incident direction, the proposed model with cavities in the diagonal direction possess a wider absorption range with a lower total thickness. Investigations under different geometrical parameters such as lattice constant are performed to study the influences of the parameters on the sound absorption of the proposed model. The findings confirm that the sound absorption bandwidth can be broadened effectively by arranging cavities in this particular way with the total thickness significantly decreased.