TY - GEN
T1 - Investigations about the modelling of acoustic properties of periodic porous materials with the shift cell approach
AU - Magliacano, D.
AU - Ouisse, M.
AU - Rosa, S. D.E.
AU - Franco, F.
AU - Khelif, A.
N1 - Publisher Copyright:
© 2019 9th ECCOMAS Thematic Conference on Smart Structures and Materials, SMART 2019. All rights reserved.
PY - 2019
Y1 - 2019
N2 - The main advantage of designing sound packages with periodic arrangements is that they can provide a combination of absorption effects, resonance effects and wave interferences effects. This offers different applications in transportation (aeronautics, space, automotive, railway), energy and civil engineering sectors, where both weight and space, as well as vibroacoustic quality of performance and comfort, still remain as critical issues. The application of shift cell technique is presented and discussed for periodic porous media described with equivalent fluid models: it consists in a reformulation of classical Floquet-Bloch (F-B) conditions, whose major advantage stands in allowing the introduction of any frequency dependence of porous material behavior, through the resolution a quadratic eigenvalue problem, providing an efficient way to compute the dispersion curves of a porous material modelled as an equivalent fluid. The central part of this work shows the results, in terms of absorption coefficient and transmission loss curves, obtained through a numerical test campaign involving different melamine and polyurethane foams. The 48 test cases involve a cubic unit cell of porous material with a cylindrical inclusion. Furthermore, some absorption coefficient and transmission loss comparisons are shown, between a homogeneous unit cell and a unit cell with a perfectly rigid inclusion; the comparisons are carried out at fixed dimensions, then at fixed mass and then at fixed performance in the periodicity peak range. The results clearly point out the advantage of designing foam layer with periodic inclusion patterns in order to improve the performances in a specific range of frequencies, allowing a save both in terms of thickness and, most of all, mass, respect to a classical homogeneous foam layer.
AB - The main advantage of designing sound packages with periodic arrangements is that they can provide a combination of absorption effects, resonance effects and wave interferences effects. This offers different applications in transportation (aeronautics, space, automotive, railway), energy and civil engineering sectors, where both weight and space, as well as vibroacoustic quality of performance and comfort, still remain as critical issues. The application of shift cell technique is presented and discussed for periodic porous media described with equivalent fluid models: it consists in a reformulation of classical Floquet-Bloch (F-B) conditions, whose major advantage stands in allowing the introduction of any frequency dependence of porous material behavior, through the resolution a quadratic eigenvalue problem, providing an efficient way to compute the dispersion curves of a porous material modelled as an equivalent fluid. The central part of this work shows the results, in terms of absorption coefficient and transmission loss curves, obtained through a numerical test campaign involving different melamine and polyurethane foams. The 48 test cases involve a cubic unit cell of porous material with a cylindrical inclusion. Furthermore, some absorption coefficient and transmission loss comparisons are shown, between a homogeneous unit cell and a unit cell with a perfectly rigid inclusion; the comparisons are carried out at fixed dimensions, then at fixed mass and then at fixed performance in the periodicity peak range. The results clearly point out the advantage of designing foam layer with periodic inclusion patterns in order to improve the performances in a specific range of frequencies, allowing a save both in terms of thickness and, most of all, mass, respect to a classical homogeneous foam layer.
KW - Foam
KW - Inclusion
KW - Periodic structure
KW - Shift cell
KW - Vibroacoustics
UR - http://www.scopus.com/inward/record.url?scp=85101998892&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85101998892
T3 - 9th ECCOMAS Thematic Conference on Smart Structures and Materials, SMART 2019
SP - 1112
EP - 1123
BT - 9th ECCOMAS Thematic Conference on Smart Structures and Materials, SMART 2019
A2 - Benjeddou, Ayech
A2 - Mechbal, Nazih
A2 - Deu, Jean-Francois
PB - International Center for Numerical Methods in Engineering
T2 - 9th ECCOMAS Thematic Conference on Smart Structures and Materials, SMART 2019
Y2 - 8 July 2019 through 11 July 2019
ER -