Improvements in panel insertion loss by addition of random masses embedded in a poro-elastic layer: Modelling procedures

Abstract

The insertion loss of standard acoustic blankets can be significantly improved at low frequencies by the addition of randomly placed mass inclusions. The improvement is much greater than that due to the mass effect alone. The mass inclusions act as vibration absorbers. This paper describes a numerical model that predicts the insertion loss of a poro-elastic layer with numerous mass inclusions. The model is based on Biots' theory for porous media and Strasbergs' work on collections of oscillators.