A general method of predicting surface impedance and transmission loss in layered media

摘要

Sound propagation of plane waves in layers of fluid and elastic solids can be modelled using transfer matrices. A similar representation has been developed for the case of porous materials having an elastic frame. Configurations including plates, impervious screens, layers of air and porous media have also been studied with this representation. These configurations can be non-locally reacting, their behaviour depends on the boundary conditions at the edges. Nevertheless, the modelling o layered media of infinite lateral dimensions can provide useful information about their acoustical and mechanical properties. A simple standard representation of porous media which uses transfer matrices is carried out. This representation can be used to predict the acoustical impedance and the transmission loss for a large variety of stratified materials.