Vibro-Acoustic Modelling of Anisotropic Porous Elastic Materials: A Preliminary Study of the Influence of Anisotropy on the Predicted Performance in a Multi-Layer Arrangement

摘要

During the recent years considerable efforts have been spent on developing numerical models and performing the necessary characterisation of elastic, dynamic and acoustic properties of porous materials. Originally having been considered to be isotropic, such materials have lately also been studied in terms of their anisotropic properties. In this paper, the influence of anisotropy on the vibroacoustic performance is illustrated and evaluated for a multi-layer configuration with varying boundary conditions between the porous material and a solid plate. The paper starts with a brief review of a recently published anisotropic, mixed displacement pressure weak formulation with a particular emphasis on the anisotropic properties. Using the material properties for a hypothetical porous foam model, the predicted response is evaluated. The influence of anisotropy is found to be significant in terms of response amplitude and apparent damping. For some boundary conditions the predicted response is an order of magnitude lower for the anisotropic material model, in particular for frequency ranges where the dynamics of the foam are significant.