NUMERICAL PREDICTION OF SOUND TRANSMISSION THROUGH MULTILAYER STRUCTURES WITH ISOTROPIC ELASTIC POROUS MATERIALS

摘要

The sound transmission performance of multilayer structures containing sound-absorbing porous materials is an important problem for noise control in aircraft and in launch vehicles. Currently, the demand of prediction tools for the acoustical and structural behaviors of such structures is considerably increasing. Also, the need of general tools capable of handling complex structures with various boundary conditions seems to favor mostly numerical methods rather than analytical methods.This paper discusses the prediction of transmission loss through multilayer structures with porous materials. A finite element model is discussed. It uses a two fields displacement formulation derived from Biot's theory. The model allows for a combination of porous, elastic and air layers. Furthermore, it couples with a variational boundary element approach to account, when important, for fluid-structure coupling and to calculate the transmission loss through the multilayer structure.