Acoustic characteristics of composite structures with 2D acoustic black holes and stiffened plates.

• A 2D acoustic black hole is referenced to the stiffened structures. • The tests of free-field sound radiation and closed cavity sound radiation were conducted. • The acoustic radiation characteristics of the ABH stiffened plate in water is analyzed. Acoustic black hole (ABH) structure, a novel technology for modulating flexural waves, offers promising solutions for controlling noise caused by structural vibrations. In this paper, we introduce acoustic black holes into traditional stiffened plate structures and design a new type of ABH stiffened plate structure, which combines the wave manipulation ability of ABH with the load-bearing capacity of the stiffened structures. We establishes finite element models for calculating the free space sound field and closed cavity sound field of an ABH stiffened plate, builds corresponding experimental platforms, and tests them under point load excitation. The results show that ABH stiffened plate has great vibration and noise reduction effects, with a 5–10 dB reduction in sound radiation power above the cut-on frequency and a maximum noise reduction of about 30 dB. Through quantitative analysis from multiple perspectives, it is shown that ABH have an inherent mechanism of increasing damping level and reducing coupling between structure and sound field. Studying the influence of different media on the acoustic radiation of ABH stiffened plates, results further reveal that ABH have noise reduction effects in water media, and increasing the application scenarios of the ABH stiffened plate structures. [ABSTRACT FROM AUTHOR]