Modelling Techniques for Vibro-Acoustic Dynamics of Poroelastic Materials

Abstract

Given the quest for mass reduction while preserving proper vibration and acoustic comfort levels in industrial machinery and vehicles, lightweight poroelastic materials have gained a lot of importance. Often, these materials are applied in a multilayered configuration, which can consist of a number of acoustic, elastic, viscoelastic and poroelastic layers. Among these, poroelastic materials are the main focus of this paper. A poroelastic material comprises two constituents, being the elastic solid constituent, also called the frame, and the fluid filling the voids. Depending on the frequency range of interest, the motion of both constituents can be strongly coupled. Poroelastic materials can dissipate energy very effectively by structural, thermal and viscous means. Considerable research effort has been put in the development of robust models and prediction techniques which are capable of accurately describing the damping phenomena of these materials. After a broad introduction, this paper reviews the most commonly used models, ranging from simple empirical relations to detailed models accounting for the coupled behaviour of both phases and the CAE modelling techniques currently being applied for the analysis of the time-harmonic vibro-acoustic behaviour of these materials. Commonly used methods, such as the Finite Element Method and the Transfer Matrix Method which are mainly fitted for low-freqency and high-frequency applications, respectively, are discussed as well as extensions to improve their efficiency and applicability. The two final sections pay special attention to the promising Wave Based Method, a Trefftz-based technique, the application range of which was recently extended towards poroelastic problems.