Mitigation of Flanking Noise in Double-Plate Panel Structures by Periodic Stiffening: finite element analysis in the low-frequency range

The present analysis focuses on flanking noise transmission within a two-wall structure of finite size. The walls are lightweight panel structures, each consisting of two plates with internal ribs. A finite-element model is utilized, assuming that the studs are fully fixed to the plates. Further, the air enclosed in the cavities within the structure is taken into consideration, whereas the external air has been disregarded. A fully coupled analysis is performed in which solid finite elements are adopted for the structure, whereas the acoustic medium within the panel is discretized into fluid continuum elements. The computations are carried out in frequency domain in the range below 500 Hz and the load acts as a concentrated force on one side of one of the panels. The responses of the same panel as well as the adjacent wall are studied.

The position of the load relative to the stiffeners is important. Hence, analyses are carried out for different positions of the load. It has been found that the ribs have a significant impact, not only on the flanking noise but also on the direct radiation of sound from the wall on which the external force has been placed. Furthermore, the response changes when the air inside the wall panels is disregarded.