Dual-cell composite acoustic covering layer with broadband absorption characteristics

A dual-cell combined acoustic covering layer has been designed and optimized, consisting of a viscoelastic rubber matrix, metal vibrators, cavities, and a steel backing. By parallel coupling the sound absorption characteristics of each cell across different frequency bands, the structural size parameters were optimized using finite element methods and genetic algorithms. The optimized covering layer exhibits an average sound absorption coefficient exceeding 0.98 in the range of 561 Hz to 15000 Hz. When adopting 0.8 as the standard for the sound absorption coefficient, an absorption range of 14439 Hz is achieved, demonstrating its wide frequency band and high sound absorption capabilities. The sound absorption mechanism of the covering layer is further revealed by analyzing the displacement and energy power dissipation distribution cloud diagrams. When the angle of sound wave incidence is 60°, the average sound absorption coefficient of the covering layer is above 0.8; even under a hydrostatic pressure of 5 MPa, the sound absorption coefficient of the covering layer remains stable above 0.8 after 595 Hz, confirming its structural stability and the durability of its sound absorption performance.