This article is a bibliographical revision concerning acoustic absorbing materials, also known as poroelastics. These absorbing materials are a passive medium use extensively in the industry to reduce noise. This review presents the fundamental parameters that define each of the parts comprising these materials, as well as current experimental methods used to measure said parameters. Further along, we will analyze the principle models of characterization in order to study the behaviour of poroelastic materials. Given the lack of accuracy of the standing wave method three absorbing materials are characterized using said principle models. A comparison between measurements with the standing wave method and the predicted surface impedance with the models is shown.

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This paper presents the problem of modeling poroelastic material on a moving structure. It presents the ambiguity of using estimated or measured surface impedance on a rigid structure as opposed to transfer impedance, which takes into account the movement of the structure to which a porous material is fixed. Biot's model for prediction of surface impedance is presented, and the transfer impedance is defined on the basis of this model. A case where several layers of porous material are fixed to a moving wall is also studied. Finally, it presents the level of agreement with experimental measurements in a coupled fluid–structure problem when an impedance considering a fixed structure and an impedance considering a moving structure are used.