Sound transmission loss for double panels using the Wave Finite Element Method

Resumo

Double panels are a usual solution for noise control. In this study, the sound transmission loss (STL)
of an infinite double panel with an air cavity and two solid layers was analyzed. The STL was calculated from
a dynamic stiffness matrix of the system, where the air layer was modeled analytically, and the solid layers were
modeled using the Wave Finite Element (WFE) method, where only one small segment of the structure is modeled
using conventional Finite Element Method (FEM), reducing the computational cost. The influence of the thickness
of the cavity and the specific masses per area of the solid layers in the STL were analyzed. Also, an optimization
procedure to maximize STL in different octave bands was performed. The results demonstrated that the WFE
method is suitable for STL calculation; that a higher STL is obtained for a wider air cavity and higher specific mass
(below coincidence frequency), and the optimization procedure led to different optimal parameters depending on
frequency because of various physical phenomena presented at a double panel.