Numerical modeling of sound transmission in double walls

Abstract

Numerical models for the calculation of sound transmission in double walls are presented. The finite element method (FEM) or analytical solutions (for rectangular domains) are used for the acoustic part of the problem while the wall vibration is solved by means of structural finite elements. The vibroacoustic problem is formulated in the frequency range: the acoustic domains (rooms) are described by the Helmholtz equation, the absorbent materials as an equivalent fluid and the structures by means of dynamic linear elasticity. The acoustic and structural parts of the problem are coupled. The influence of the stiffness and spacing of the studs on the performance of lightweight walls is studied. The studs have been modelled with beam finite elements or by means of mechanical constraints. The effect of the boundary conditions of the walls and its dimensions are also analyzed.