Noise reduction inside a cavity coupled to a flexible plate with embedded 2-D acoustic black holes

Wavenumber domain analyses of vibro-acoustic decoupling and noise attenuation in a plate-cavity system enclosed by an acoustic black hole plate

“…(A3) are used to evaluate the vibration level of the plate and the sound field inside the cavity, respectively. 19 Equations (A11)-(A13) show that the complex amplitude of the ith acoustic mode depends on the coupling coefficient, C i , between this acoustic mode and the displacement field over the plate-cavity interface, which includes the contribution from all the structural modes. Equation (A15) shows that the quadratic space-averaged sound pressure in the cavity is directly determined by the squared modulus of the coupling coefficient, C i C Ã i .…”

“…The potential benefit of using ABH design for interior noise reduction was investigated in our previous work using a four ABH grid configuration. 19 The cavity configuration, however, was limited to a regular rectangular cavity in which modal coupling takes place in a very selective manner. In fact, in a cavity with simple regular geometry, both the structural modes and the acoustic modes take regular shapes at the interface, and their a) Electronic mail: qiu@nuaa.edu.cn coupling shows relatively simple patterns.…”

“…Using two different configurations, system response is computed through a finite element model, following a procedure which was validated in a former study. 19 A wavenumber domain method (WNDM) is proposed for the analysis of vibro-acoustic coupling behavior and the internal noise reduction mechanism, after deriving the relationship between the space-averaged sound energy inside the cavity and the spectra of the structural displacement and the acoustic mode of the cavity. Through Fourier transforms, the expressions in the spatial domain are transformed into the wavenumber domain.…”

“…12 In the present case, the WNDM is used for further revealing the underlying mechanisms of the ABH-induced interior noise reduction under a fully coupled vibro-acoustic context. Compared with the method based on the modal coupling coefficients, 19 the WNDM offers the advantage of examining the entire displacement field of the structure coupled with a specific acoustic mode. Numerical results indicate that the redistribution of the displacement spectrum in the wavenumber domain induced by local vibration modes in the ABH structure is the main reason leading to the noise reduction in the cavity.…”

Effects of Acoustic Black Hole Parameters and Damping Layer on Sound Insulation Performance of ABH Circular Plate

“…Li et al presented analytical solutions of sound radiation of a beam with a wedge-shaped edge embedding ABH by using the transfer matrix method (TMM) [14]. Ji et al established a numerical finite element model of acoustic radiation considering plate-cavity coupling and proposed that the damping enhancement and the coupling strength decreasing between the plate and the cavity are two mechanisms for the intracavity noise reduction [15]. Wang et al proposed a wavenumber domain method (WNDM) for the analysis of vibro-acoustic coupling and internal noise reduction mechanism of a pentahedral cavity enclosed by a flexible plate with a two-dimensional ABH indentation [16].…”