Sensitivity of macroscopic properties of a multi-layer panel including porous material on the micro-level parameters of an open cell porous material
2014 (English)In: PROCEEDINGS OF INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING (ISMA2014) AND INTERNATIONAL CONFERENCE ON UNCERTAINTY IN STRUCTURAL DYNAMICS (USD2014), 2014, 2135-2149 p.Conference paper (Refereed)
The micro-structure of an open cell porous material is modelled as an idealized, periodic structure, allowing anisotropic properties to form on the micro-scale. Using simple analytic descriptions of acoustic and elastic properties calculated from micro-structure geometry, the microstructural properties can be linked to averaged macroscopic elasto-acoustic properties, which can be measured and observed. These macro level properties may be deduced from measurements on a sample of a porous material which is at least a few centimetres across. The most common of the acoustic properties are the flow resistivity or the (dynamic) permeability, the porosity and the viscous and thermal characteristic lengths, together with the tortuosity. For the elasticity, the moduli of the Hooke's law are the most important. The underlying motivation for the current work is that the quantities are interdependent since they all depend on the micro geometry. Thus, to design the macro level acoustic properties for a required performance, physically relevant models linking these to the micro structure would be necessary. In this paper, a set of such models are proposed and utilising these, the influence of the anisotropy on acoustic properties of the foam as well as the transmission loss of a multi-layer plate is investigated. Typical macro level acoustic properties of open cell poro-elastic materials calculated from micro structure parameters are found to give results of the same order of magnitude as measured data found in the literature. Further, the model is applied to evaluate transmission loss of roof constructions with isotropic and anisotropic foam. It is shown that the sound reduction can be improved without changing the overall surface weight of the structure by making use of the anisotropy of the foam. The results Underline the importance of anisotropy and in addition provide guidance for further research.
Place, publisher, year, edition, pages
2014. 2135-2149 p.
IdentifiersURN: urn:nbn:se:kth:diva-164938ISI: 000352201002045ScopusID: 2-s2.0-84913591667ISBN: 978-907380291-9OAI: oai:DiVA.org:kth-164938DiVA: diva2:806522
International Conference on Noise and Vibration Engineering (ISMA), Leuven, BELGIUM, SEP 15-17, 2014
QC 201505122015-04-202015-04-202016-05-23Bibliographically approved