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Dataset Open Access

# Statistical characterisation and responses of acoustic screens and two-layers systems

Mathieu Gaborit; Luc Jaouen; Olivier Dazel; Peter Göransson

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{
"publisher": "Zenodo",
"DOI": "10.5281/zenodo.3358921",
"language": "eng",
"title": "Statistical characterisation and responses of acoustic screens and two-layers systems",
"issued": {
"date-parts": [
[
2019,
8,
2
]
]
},
"abstract": "<p>The present dataset contains measurements of the acoustic response of screens in an impedance tube with different backings. It includes as well the characterised parameters for the screens and backings.</p>\n\n<p><strong>License</strong></p>\n\n<p>This dataset is released under Creative Commons with Attribution (CC BY). Any reutilisation of the present dataset in scholarly works must properly cite this work and its authors:</p>\n\n<pre><code>Statistical characterisation and responses of acoustics screens and two-layers systems\nM. Gaborit, L. Jaouen, O. Dazel, P. G\u00f6ransson\nDOI: 10.5281/zenodo.3358921\n</code></pre>\n\n<p><strong>Protocol</strong></p>\n\n<p>Two different films (one woven and one non-woven) were sampled 40 times in order to characterise their parameters in an impedance tube. Sampling is manual, the tube inner diameter is 44.44mm and the samples are cut to a slightly large size in order to be clamped inside the tube for measurements.</p>\n\n<p>The films are tested in different configurations including some with backings. Two types of backings are considered (melamine and glass wool). These backings are also characterised using 3 and 2 samples respectively. When measuring the response of the film on a backing only 20 samples of each film were used.</p>\n\n<p>All measurements span the [4, 4520] Hz band. The setup is calibrated anew before each measurement session.</p>\n\n<p><strong>Films&#39; characterisation</strong></p>\n\n<p>The films are clamped in the seam between the two parts of the tube, a 200mm air plenum is formed downstream and ends with a rigid backing. The samples for each type of film are measured within 4h.</p>\n\n<p>The characterisation procedure implements the method described in the following reference:</p>\n\n<ul>\n\t<li>Jaouen L. B&eacute;cot F.-X. JASA 129(3) pp. 1400 - 1406, 2011</li>\n</ul>\n\n<p><strong>Backings&#39; characterisation</strong></p>\n\n<p>The sample and backing piston are placed to give a rigid backing and have the sample&#39;s surface flush with the seam between the two parts of the tube. In the case of the glass wool, the material has a slight (below millimetre) embossing and the supporting surface is placed flush with respect to the seam (the top of the embossing is not considered as the sample surface).</p>\n\n<p>The characterisation procedure implements the method described in the following references:</p>\n\n<ul>\n\t<li>Olny, X. &amp; Panneton, R. JASA 123(2) pp. 814 &ndash; 824, 2008</li>\n\t<li>Panneton R. &amp; Olny, X. JASA 119(4), p. 2027, 2006</li>\n</ul>\n\n<p><strong>Response measurements</strong></p>\n\n<p>To measure responses of the film/backing systems, the backing are placed as described in the previous paragraph. The film is clamped in the seam as described in the &quot;Films&#39; characterisation&quot; section. A plastic grid with thin struts is placed upstream to prevent the film from bending. This setup allows for easily changing the film without replacing the backing sample. Films&#39; samples 1 to 20 are used for response measurements. Measurement of the grid response on a rigid backing and an air plenum of 200mm are provided for reference.</p>\n\n<p><strong>Hardware</strong></p>\n\n<ul>\n\t<li><a href=\"http://www.mecanum.com/en/products/impedance-tube/impedance-and-transmission-tube-3-mic/\">Mecanum 3-microphones tube, diameter: 44.44mm</a></li>\n</ul>\n\n<p><strong>Software</strong></p>\n\n<ul>\n\t<li><a href=\"http://tubecell.matelys.com/\">Matelys TubeCell</a> (rig control)</li>\n\t<li><a href=\"http://rokcell.matelys.com/\">Matelys RoKCell</a> (characterisation)</li>\n</ul>\n\n<p>The piece of software controlling the rig implements a 3-microphones technique described in the following references:</p>\n\n<ul>\n\t<li>Iwase T. Izumi Y. J. Acoust. Soc. Jpn J 52(6) pp. 411&ndash;419, 1996 (in Japanese)</li>\n\t<li>Iwase T. Izumi Y. Kawabata R. in proc. Internoise, 1998 (Christchurch, New Zealand)</li>\n</ul>\n\n<p><strong>Structure of the datasets and files</strong></p>\n\n<p>The present dataset comprises two parts. The actual traces and associated measurement parameters as exported from TubeCell are found in the directory <code>measurements</code>. The results from the characterisation process as exported with RoKCell are in the <code>characterisations</code> folder. These results were augmented with direct measurements of the weights and thickness of the samples (both for the films and the backings).</p>\n\n<p><strong>Measurements</strong></p>\n\n<p>The measurements are stored in the <code>measurements</code> directory. There are several sub-directory for each of the measurement sessions:</p>\n\n<ul>\n\t<li><code>backings</code>: measurements for the caracterisation of the two backings (all samples, with and without grid)</li>\n\t<li><code>grid</code>: measurements of the grid alone on a rigid backing and with a 200mm air plenum</li>\n\t<li><code>nonwoven_alone</code>: measurements for the caracterisation of the non-woven film on a 200mm air plenum, no grid (all 40 samples)</li>\n\t<li><code>woven_alone</code>: measurements for the caracterisation of the woven film on a 200mm air plenum, no grid (all 40 samples)</li>\n\t<li><code>nonwoven_on_glasswool</code>: measurements of the response of 20 non-woven film samples clamped with a grid upstream and the same glass wool sample downstream on a rigid backing</li>\n\t<li><code>nonwoven_on_melamine</code>: measurements of the response of 20 non-woven film samples clamped with a grid upstream and the same melamine sample downstream on a rigid backing</li>\n\t<li><code>woven_on_glasswool</code>: measurements of the response of 20 woven film samples clamped with a grid upstream and the same glass wool sample downstream on a rigid backing</li>\n\t<li><code>woven_on_melamine</code>: measurements of the response of 20 woven film samples clamped with a grid upstream and the same melamine sample downstream on a rigid backing</li>\n</ul>\n\n<p>Each measurement is stored into a <code>.irk</code> <em>and</em> a <code>.rok</code> file. The first one contains some meta-data on the measurement process, the second contains the actual traces.</p>\n\n<p><strong>Structure of irk files</strong></p>\n\n<p>The <code>.irk</code> files contain the following meta-data:</p>\n\n<ul>\n\t<li>Date</li>\n\t<li>Medium ID</li>\n\t<li>Thickness</li>\n\t<li>Size of the air plenum</li>\n\t<li>Measure parameter l</li>\n\t<li>Measure parameter s</li>\n\t<li>Sampling frequency</li>\n\t<li>Tube radius [m]</li>\n\t<li>Average 1</li>\n\t<li>Average 2</li>\n\t<li>Temperature [&deg;C]</li>\n\t<li>Atmospheric pressure [Pa]</li>\n\t<li>Humidity [%]</li>\n\t<li>High cut-off frequency (generator) [Hz]</li>\n\t<li>Low cut-off frequency (generator) [Hz]</li>\n\t<li>Position of the cavity microphone</li>\n\t<li>Comments</li>\n</ul>\n\n<p><strong>Structure of rok files</strong></p>\n\n<p>The <code>.rok</code> files contain the following vector (column-major). The first line is to be omitted when reading the files, it contains the columns title. The columns are these:</p>\n\n<ul>\n\t<li>Frequency (Hz)</li>\n\t<li>Absorption coefficient</li>\n\t<li>Real part of the reflection coefficient</li>\n\t<li>Imaginary part of the reflection coefficient</li>\n\t<li>Real part of the normalised surface impedance</li>\n\t<li>Imaginary part of the normalised surface impedance</li>\n\t<li>Real part of the transfer function</li>\n\t<li>Imaginary part of the transfer function</li>\n\t<li>Real part of the normalised density</li>\n\t<li>Imaginary part of the normalised density</li>\n\t<li>Real part of the normalised compressibility</li>\n\t<li>Imaginary part of the normalised compressibility</li>\n\t<li>... frequency response functions used to compute the previous quantities</li>\n</ul>\n\n<p><strong>Characterisations</strong></p>\n\n<p>The directory <code>characterisations</code> contains YAML 1.2 files created from the output files of the characterisation software, exploiting the measurement data. There are three subdirectories:</p>\n\n<ul>\n\t<li><code>backings</code> contains the characterisation of the backings (each sample and an average file)</li>\n\t<li><code>nonwoven</code> contains the characterisation of the non-woven film (each sample and an average file)</li>\n\t<li><code>woven</code> contains the characterisation of the woven film (each sample and an average file)</li>\n</ul>\n\n<p><strong>More information</strong></p>\n\n<p>For further inquiry write to gaborit at kth dot se</p>",
"author": [
{
"family": "Mathieu Gaborit"
},
{
"family": "Luc Jaouen"
},
{
"family": "Olivier Dazel"
},
{
"family": "Peter G\u00f6ransson"
}
],
"version": "1.0",
"type": "dataset",
"id": "3358921"
}
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