Broadband sound transmission loss in a corrugated sound panel using periodic structure theory

The vibration and sound radiation characteristics of a double leaf panel wall with corrugated core are analyzed. The core comprises of repeating unit cell along the length of the panel. Each cell is a combination of a straight beam with uniform cross-section and curved beams with varying cross-section. The vibroacoustics property of the corrugated panel is analysed assuming plain strain condition. The analysis presented in the work shows that the proposed sandwich panel design provides broadband sound transmission loss (STL) characteristics. The dispersion analysis, forced response characteristics and sound radiation characteristics of the structure are presented. It is found that bending frequency band gap obtained from the dispersion analysis is a prominent criterion to achieve a higher STL. The structural and acoustic behaviours of the sandwich panel are analysed through the spectral finite element model. The STL for the core element for various taper ratios is presented. It is found that a higher taper ratio shifts the STL characteristics to the low frequency range.