Acoustic treatment via membrane-type metamaterials

Abstract

Metamaterials have recently emerged as means for exploring phenomenapreviously related to electromagnetic wave propagation in systems subject to mechanicalwaves (structural and/or acoustic) waves. Among these phenomena, the Bragg dispersionand local resonance phenomena are highlighted, both found in periodic structures, whichpromote energy attenuation in certain frequency bands - the so-called band gaps. Thisnew paradigm in materials, as described and demonstrated in the literature, offerscompetitive solutions from the point of view of performance and mass load, offering aninteresting alternative for the control of noise and vibrations with potential of applicationsin diverse areas of the engineering. Therefore, this master thesis aims at the numericaland experimental study of membrane acoustic metamaterials, a bi-dimensionalconfiguration of compact and lightweight resonant structures suitable for noiseattenuation and architectural acoustic treatment. Novel membrane metamaterial conceptsshould arise from the proposed study, whose application shall promote scientific andtechnological development. In order to do so, the research plan involves activities ofdesign, numeric-computational simulation and validation of unit cells, in order to adjusttheir dynamic properties. Afterwards, the performance of a group of cells grouped in aperiodic pattern shall be evaluated in terms of attenuation range and bandgap width,envisioning applications in noise reductions by means of absorption, transmission andscattering. (AU)