The acoustic characterization of porous media and its ...ISO 4590 (porosity, not always convenient...
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The acoustic characterization of porous media and its standards ISO 9053 (resistivity, under revision) ISO 9237 (Textiles -- Determination of the permeability of fabrics to air) ISO 4590 (porosity, not always convenient for acoustical porous media) ISO 10534-2 (normal surface impedance, revision scheduled) ISO 6721 series (elastic moduli) ISO 18437-5 (Poisson's ratio[s]) L. Jaouen, F.-X. Bécot, F. Chevillotte with acknowledgements to P. Bonfiglio & K. Horoshenkov
Transcript of The acoustic characterization of porous media and its ...ISO 4590 (porosity, not always convenient...
The acoustic characterization of porous mediaand its standards
ISO 9053 (resistivity, under revision)
ISO 9237 (Textiles -- Determination of the permeability of fabrics to air)
ISO 4590 (porosity, not always convenient for acoustical porous media)
ISO 10534-2 (normal surface impedance, revision scheduled)
ISO 6721 series (elastic moduli)
ISO 18437-5 (Poisson's ratio[s])
L. Jaouen, F.-X. Bécot, F. Chevillotte
with acknowledgements toP. Bonfiglio & K. Horoshenkov
Details
Do we need [to improve] standards ?
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Do we need [to improve] standards ?Case of a benchmark involving 7 laboratories (same samples of materials)
1000 2000 3000 4000 5000 60000
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0.4
0.6
0.8
1
Frequency (Hz)
Sound absorption coefficient (normal incidence)
Melamine foam (open pores)
Measurements in impedance tubes following ISO 10534-23
Do we need [to improve] standards ?Case of a benchmark involving 7 laboratories (same samples of materials)
1000 2000 3000 4000 5000 60000
0.2
0.4
0.6
0.8
1
Frequency (Hz)
Sound absorption coefficient (normal incidence)
Coustone(granular)
Measurements in impedance tubes following ISO 10534-24
Do we need [to improve] standards ?Case of a benchmark involving 7 laboratories (same samples of materials)
1000 2000 3000 4000 5000 60000
0.2
0.4
0.6
0.8
1
Frequency (Hz)
Sound absorption coefficient (normal incidence)
Armasound(semi-closed pores)
Measurements in impedance tubes following ISO 10534-25
Do we need [to improve] standards ?Case of a benchmark involving 6 laboratories (same samples of materials)
10 000
15 000
5 000
0
Melamine foam(open pores)
Static airflow resistivity
10 900± 700
11 000± 500
16 400± 200
9 700± 400
8 800± 500
10 400± 500
Measurements following ISO 9053(mostly without strict conformity to the standard)
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Do we need [to improve] standards ?Case of a benchmark involving 6 laboratories (same samples of materials)
10 000
0
Static airflow resistivity
40 500± 5 100
15 900± 100
20 000
30 000
40 000
50 000
Coustone(granular)
47 100± 5 100
25 800± 4 700
26 400± 3 300
41 200± 5 900
Measurements following ISO 9053(mostly without strict conformity to the standard)
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Do we need [to improve] standards ?Case of a benchmark involving 6 laboratories (same samples of materials)
Static airflow resistivity
210 000± 46 700
133 300± 13 100
50 000
Armasound(semiclosed pores)
205 700± 11 000
115 300± 16 400
274 200± 65 400
254 500± 56 000
0
150 000
100 000
250 000
300 000
200 000
Measurements following ISO 9053(mostly without strict conformity to the standard)
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Do we need [to improve] standards ?Obvioulsy: yes concerning ISO 9053.
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Currently:Diameter (edge) of the samples ≥ 95 (90) mm (leakage may be negligible if ratio area / perimeter is largebut a leakage is a leakage and we test permeable materials ! )
Proposition:Diameter depending on Representative Elementary Volume,examples :29 mm minimum for a foam with small pores95 mm for a granular road pavement.
Some propositions for ISO 9053 revision(Static-air flow resistivity measurement)
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Details
Currently:Superimposed samples with small thickness up to a max of 5
Observation & proposition:Obviously it cannot be applied to all morphologies.(Add an informative note about the estimation using an impedance tubefor perforated plates, woven / non-woven screens and other facings)
Some propositions for ISO 9053 revision(Static-air flow resistivity measurement)
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Details
Proposition:Addition of 3- & 4- microphones methods (as in ASTM E2611)(Explaining what one can do and what one cannot do we willprevent diffuse field computations from TL measurements in tube)
Proposition:Addition of estimations for dynamic mass density and bulk modulus(leading to estimation of acoustic parameters forthe Johnson-Champoux-Allard-Lafarge model)
Some propositions for ISO 10534-2 revision(Impedance tube measurements)
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Details
Often read in current standards:"Inter-laboratory experiments are planned"
Ongoing work:Inter-laboratory test started (more than 10 labs, 5 different materials). First results should be presented in 2017(probably during next SAPEM in Le Mans ).
Concerning elastic parameters
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