tdehaeze/nass-micro-station-measurements
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
master
nass-micro-station-measurem.../2018-01-12 - Marc/index.html

481 lines
20 KiB
HTML
Raw Permalink Blame History

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<!-- 2020-11-12 jeu. 10:26 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<title>Measurements</title>
<meta name="generator" content="Org mode" />
<meta name="author" content="Dehaeze Thomas" />
<link rel="stylesheet" type="text/css" href="https://research.tdehaeze.xyz/css/style.css"/>
<script type="text/javascript" src="https://research.tdehaeze.xyz/js/script.js"></script>
</head>
<body>
<div id="org-div-home-and-up">
<a accesskey="h" href="../index.html"> UP </a>
|
<a accesskey="H" href="../index.html"> HOME </a>
</div><div id="content">
<h1 class="title">Measurements</h1>
<div id="table-of-contents">
<h2>Table of Contents</h2>
<div id="text-table-of-contents">
<ul>
<li><a href="#orgf7b0b7a">1. Experimental conditions</a></li>
<li><a href="#org01526bf">2. Measurements procedure</a></li>
<li><a href="#org5428c6f">3. Measurement Channels</a></li>
<li><a href="#org083916b">4. Experiments</a></li>
<li><a href="#orga6855fa">5. Data Analysis</a>
<ul>
<li><a href="#orgf4e2716">5.1. Loading and pre-processing of the data</a></li>
<li><a href="#orged9d5af">5.2. X-direction FRF</a></li>
<li><a href="#orgc5bca15">5.3. Y-direction FRF</a></li>
<li><a href="#org281b6fd">5.4. Z-direction FRF</a></li>
<li><a href="#org79b392d">5.5. Save the processed data</a></li>
</ul>
</li>
<li><a href="#orgfbc6e27">6. Results</a></li>
</ul>
</div>
</div>
<div id="outline-container-orgf7b0b7a" class="outline-2">
<h2 id="orgf7b0b7a"><span class="section-number-2">1</span> Experimental conditions</h2>
<div class="outline-text-2" id="text-1">
<table border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<colgroup>
<col class="org-left" />
<col class="org-left" />
</colgroup>
<tbody>
<tr>
<td class="org-left"><b>Date</b></td>
<td class="org-left">2018-01-12</td>
</tr>
<tr>
<td class="org-left"><b>Sensors</b></td>
<td class="org-left">Geophones</td>
</tr>
<tr>
<td class="org-left"><b>Excitation</b></td>
<td class="org-left">Instrumented Hammer</td>
</tr>
<tr>
<td class="org-left"><b>Location</b></td>
<td class="org-left">Laboratory</td>
</tr>
<tr>
<td class="org-left"><b>Notes</b></td>
<td class="org-left">Unglued Granite</td>
</tr>
</tbody>
</table>
<ul class="org-ul">
<li>The granite is not glued to the floor</li>
<li>FS = 512Hz</li>
<li>Made by Marc Lesourd on the 12 of January 2018</li>
</ul>
<p>
<b>Goal</b>:
Obtain better coherence at low frequency.
</p>
</div>
</div>
<div id="outline-container-org01526bf" class="outline-2">
<h2 id="org01526bf"><span class="section-number-2">2</span> Measurements procedure</h2>
<div class="outline-text-2" id="text-2">
<p>
<b>Geophones</b>
L-28LB geophones (table <a href="#orgef0c0ef">1</a>) are placed on
</p>
<ul class="org-ul">
<li>Marle</li>
<li>Tilt Stage</li>
<li>Top of Hexapod</li>
</ul>
<table id="orgef0c0ef" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 1:</span> L-28LB Geophone characteristics</caption>
<colgroup>
<col class="org-left" />
<col class="org-right" />
</colgroup>
<tbody>
<tr>
<td class="org-left">Natural Frequency [Hz]</td>
<td class="org-right">4.5</td>
</tr>
<tr>
<td class="org-left">Weight [g]</td>
<td class="org-right">140</td>
</tr>
<tr>
<td class="org-left">Sensitivity [V/(m/s)]</td>
<td class="org-right">31.3</td>
</tr>
</tbody>
</table>
<p>
The structure is excited using an <b>instrumented hammer</b> with impacts on
</p>
<ul class="org-ul">
<li>Marble X-Y-Z</li>
<li>Hexapod X-Y-Z</li>
</ul>
</div>
</div>
<div id="outline-container-org5428c6f" class="outline-2">
<h2 id="org5428c6f"><span class="section-number-2">3</span> Measurement Channels</h2>
<div class="outline-text-2" id="text-3">
<table id="org2f154cd" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 2:</span> Description of each measurement channel</caption>
<colgroup>
<col class="org-right" />
<col class="org-left" />
<col class="org-left" />
<col class="org-left" />
</colgroup>
<thead>
<tr>
<th scope="col" class="org-right">Ch. nb</th>
<th scope="col" class="org-left">Element</th>
<th scope="col" class="org-left">Location</th>
<th scope="col" class="org-left">Direction</th>
</tr>
</thead>
<tbody>
<tr>
<td class="org-right">1</td>
<td class="org-left">Hammer</td>
<td class="org-left">variable</td>
<td class="org-left">&#xa0;</td>
</tr>
</tbody>
<tbody>
<tr>
<td class="org-right">2</td>
<td class="org-left">Geophone</td>
<td class="org-left">Marble</td>
<td class="org-left">X-Y-Z</td>
</tr>
<tr>
<td class="org-right">3</td>
<td class="org-left">Geophone</td>
<td class="org-left">Tilt stage</td>
<td class="org-left">X-Y-Z</td>
</tr>
<tr>
<td class="org-right">4</td>
<td class="org-left">Geophone</td>
<td class="org-left">Top of Hexapod</td>
<td class="org-left">X-Y-Z</td>
</tr>
</tbody>
</table>
</div>
</div>
<div id="outline-container-org083916b" class="outline-2">
<h2 id="org083916b"><span class="section-number-2">4</span> Experiments</h2>
<div class="outline-text-2" id="text-4">
<table id="org1021f8b" border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<caption class="t-above"><span class="table-number">Table 3:</span> Description of the location of direction of the excitation for each measurement</caption>
<colgroup>
<col class="org-right" />
<col class="org-left" />
<col class="org-left" />
</colgroup>
<thead>
<tr>
<th scope="col" class="org-right">Meas. nb</th>
<th scope="col" class="org-left">Location</th>
<th scope="col" class="org-left">Direction</th>
</tr>
</thead>
<tbody>
<tr>
<td class="org-right">1</td>
<td class="org-left">Marble</td>
<td class="org-left">X</td>
</tr>
<tr>
<td class="org-right">2</td>
<td class="org-left">Hexapod</td>
<td class="org-left">X</td>
</tr>
</tbody>
<tbody>
<tr>
<td class="org-right">3</td>
<td class="org-left">Marble</td>
<td class="org-left">Y</td>
</tr>
<tr>
<td class="org-right">4</td>
<td class="org-left">Hexapod</td>
<td class="org-left">Y</td>
</tr>
</tbody>
<tbody>
<tr>
<td class="org-right">5</td>
<td class="org-left">Marble</td>
<td class="org-left">Z</td>
</tr>
<tr>
<td class="org-right">6</td>
<td class="org-left">Hexapod</td>
<td class="org-left">Z</td>
</tr>
</tbody>
</table>
</div>
</div>
<div id="outline-container-orga6855fa" class="outline-2">
<h2 id="orga6855fa"><span class="section-number-2">5</span> Data Analysis</h2>
<div class="outline-text-2" id="text-5">
</div>
<div id="outline-container-orgf4e2716" class="outline-3">
<h3 id="orgf4e2716"><span class="section-number-3">5.1</span> Loading and pre-processing of the data</h3>
<div class="outline-text-3" id="text-5-1">
<p>
The Geophone sensitivity is defined below:
</p>
<div class="org-src-container">
<pre class="src src-matlab">w0 = 4.5<span class="org-type">*</span>2<span class="org-type">*</span><span class="org-constant">pi</span>; <span class="org-comment">% [rad/s]</span>
ksi = 0.38;
G0 = 31.3; <span class="org-comment">% [V/(m/s)]</span>
G = G0<span class="org-type">*</span>(s<span class="org-type">/</span>w0)<span class="org-type">^</span>2<span class="org-type">/</span>((s<span class="org-type">/</span>w0)<span class="org-type">^</span>2 <span class="org-type">+</span> 2<span class="org-type">*</span>ksi<span class="org-type">*</span>(s<span class="org-type">/</span>w0) <span class="org-type">+</span> 1); <span class="org-comment">% [V/(m/s)]</span>
</pre>
</div>
<p>
We then:
</p>
<ul class="org-ul">
<li>load the data</li>
<li>add a minus sign when needed</li>
<li>integrate the signal to have displacement instead of velocity</li>
<li>scaled with the sensitivity of the Geophone</li>
</ul>
<div class="org-src-container">
<pre class="src src-matlab">load(<span class="org-string">'./raw_data/freq_frf.mat'</span>) <span class="org-comment">% freq_frf</span>
w = <span class="org-constant">j</span><span class="org-type">*</span>2<span class="org-type">*</span><span class="org-constant">pi</span><span class="org-type">*</span>freq_frf; <span class="org-comment">% j.omega in [rad/s]</span>
scaling = squeeze(freqresp(G, 2<span class="org-type">*</span><span class="org-constant">pi</span><span class="org-type">*</span>freq_frf))<span class="org-type">/</span>G0;
load(<span class="org-string">'./raw_data/frf_marble_x.mat'</span>) <span class="org-comment">% ReIm1</span>
frf_marble_x = zeros(size(ReIm1, 1), 3);
frf_marble_x(<span class="org-type">:</span>, 1) = <span class="org-type">-</span>ReIm1(<span class="org-type">:</span>, 2)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% marble_x</span>
frf_marble_x(<span class="org-type">:</span>, 2) = <span class="org-type">-</span>ReIm1(<span class="org-type">:</span>, 3)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% tilt_x</span>
frf_marble_x(<span class="org-type">:</span>, 3) = <span class="org-type">-</span>ReIm1(<span class="org-type">:</span>, 4)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% hexa_x</span>
load(<span class="org-string">'./raw_data/frf_hexa_x.mat'</span>) <span class="org-comment">% ReIm2</span>
frf_hexa_x = zeros(size(ReIm2, 1), 3);
frf_hexa_x(<span class="org-type">:</span>, 1) = <span class="org-type">-</span>ReIm2(<span class="org-type">:</span>, 2)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% marble_x</span>
frf_hexa_x(<span class="org-type">:</span>, 2) = <span class="org-type">-</span>ReIm2(<span class="org-type">:</span>, 3)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% tilt_x</span>
frf_hexa_x(<span class="org-type">:</span>, 3) = <span class="org-type">-</span>ReIm2(<span class="org-type">:</span>, 4)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% hexa_x</span>
load(<span class="org-string">'./raw_data/frf_marble_y.mat'</span>) <span class="org-comment">% ReIm3</span>
frf_marble_y = zeros(size(ReIm3, 1), 3);
frf_marble_y(<span class="org-type">:</span>, 1) = <span class="org-type">-</span>ReIm3(<span class="org-type">:</span>, 2)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% marble_y</span>
frf_marble_y(<span class="org-type">:</span>, 2) = <span class="org-type">-</span>ReIm3(<span class="org-type">:</span>, 3)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% tilt_y</span>
frf_marble_y(<span class="org-type">:</span>, 3) = <span class="org-type">-</span>ReIm3(<span class="org-type">:</span>, 4)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% hexa_y</span>
load(<span class="org-string">'./raw_data/frf_hexa_y.mat'</span>) <span class="org-comment">% ReIm4</span>
frf_hexa_y = zeros(size(ReIm4, 1), 3);
frf_hexa_y(<span class="org-type">:</span>, 1) = ReIm4(<span class="org-type">:</span>, 2)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% marble_y</span>
frf_hexa_y(<span class="org-type">:</span>, 2) = ReIm4(<span class="org-type">:</span>, 3)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% tilt_y</span>
frf_hexa_y(<span class="org-type">:</span>, 3) = ReIm4(<span class="org-type">:</span>, 4)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% hexa_y</span>
load(<span class="org-string">'./raw_data/frf_marble_z.mat'</span>) <span class="org-comment">% ReIm5</span>
frf_marble_z = zeros(size(ReIm5, 1), 3);
frf_marble_z(<span class="org-type">:</span>, 1) = ReIm5(<span class="org-type">:</span>, 2)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% marble_z</span>
frf_marble_z(<span class="org-type">:</span>, 2) = ReIm5(<span class="org-type">:</span>, 3)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% tilt_z</span>
frf_marble_z(<span class="org-type">:</span>, 3) = ReIm5(<span class="org-type">:</span>, 4)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% hexa_z</span>
load(<span class="org-string">'./raw_data/frf_hexa_z.mat'</span>) <span class="org-comment">% ReIm6</span>
frf_hexa_z = zeros(size(ReIm6, 1), 3);
frf_hexa_z(<span class="org-type">:</span>, 1) = ReIm6(<span class="org-type">:</span>, 2)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% marble_z</span>
frf_hexa_z(<span class="org-type">:</span>, 2) = ReIm6(<span class="org-type">:</span>, 3)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% tilt_z</span>
frf_hexa_z(<span class="org-type">:</span>, 3) = ReIm6(<span class="org-type">:</span>, 4)<span class="org-type">./</span>w<span class="org-type">./</span>scaling; <span class="org-comment">% hexa_z</span>
</pre>
</div>
<div class="org-src-container">
<pre class="src src-matlab">load(<span class="org-string">'./raw_data/coher_marble_x.mat'</span>) <span class="org-comment">% coh1</span>
coh_marble_x = zeros(size(coh1, 1), 3);
coh_marble_x(<span class="org-type">:</span>, 1) = coh1(<span class="org-type">:</span>, 2); <span class="org-comment">% marble_x</span>
coh_marble_x(<span class="org-type">:</span>, 2) = coh1(<span class="org-type">:</span>, 3); <span class="org-comment">% tilt_x</span>
coh_marble_x(<span class="org-type">:</span>, 3) = coh1(<span class="org-type">:</span>, 4); <span class="org-comment">% hexa_x</span>
load(<span class="org-string">'./raw_data/coher_hexa_x.mat'</span>) <span class="org-comment">% coh2</span>
coh_hexa_x = zeros(size(coh2, 1), 3);
coh_hexa_x(<span class="org-type">:</span>, 1) = coh2(<span class="org-type">:</span>, 2); <span class="org-comment">% marble_x</span>
coh_hexa_x(<span class="org-type">:</span>, 2) = coh2(<span class="org-type">:</span>, 3); <span class="org-comment">% tilt_x</span>
coh_hexa_x(<span class="org-type">:</span>, 3) = coh2(<span class="org-type">:</span>, 4); <span class="org-comment">% hexa_x</span>
load(<span class="org-string">'./raw_data/coher_marble_y.mat'</span>) <span class="org-comment">% coh3</span>
coh_marble_y = zeros(size(coh3, 1), 3);
coh_marble_y(<span class="org-type">:</span>, 1) = coh3(<span class="org-type">:</span>, 2); <span class="org-comment">% marble_y</span>
coh_marble_y(<span class="org-type">:</span>, 2) = coh3(<span class="org-type">:</span>, 3); <span class="org-comment">% tilt_y</span>
coh_marble_y(<span class="org-type">:</span>, 3) = coh3(<span class="org-type">:</span>, 4); <span class="org-comment">% hexa_y</span>
load(<span class="org-string">'./raw_data/coher_hexa_y.mat'</span>) <span class="org-comment">% coh4</span>
coh_hexa_y = zeros(size(coh4, 1), 3);
coh_hexa_y(<span class="org-type">:</span>, 1) = coh4(<span class="org-type">:</span>, 2); <span class="org-comment">% marble_y</span>
coh_hexa_y(<span class="org-type">:</span>, 2) = coh4(<span class="org-type">:</span>, 3); <span class="org-comment">% tilt_y</span>
coh_hexa_y(<span class="org-type">:</span>, 3) = coh4(<span class="org-type">:</span>, 4); <span class="org-comment">% hexa_y</span>
load(<span class="org-string">'./raw_data/coher_marble_z.mat'</span>) <span class="org-comment">% coh5</span>
coh_marble_z = zeros(size(coh5, 1), 3);
coh_marble_z(<span class="org-type">:</span>, 1) = coh5(<span class="org-type">:</span>, 2); <span class="org-comment">% marble_z</span>
coh_marble_z(<span class="org-type">:</span>, 2) = coh5(<span class="org-type">:</span>, 3); <span class="org-comment">% tilt_z</span>
coh_marble_z(<span class="org-type">:</span>, 3) = coh5(<span class="org-type">:</span>, 4); <span class="org-comment">% hexa_z</span>
load(<span class="org-string">'./raw_data/coher_hexa_z.mat'</span>) <span class="org-comment">% coh6</span>
coh_hexa_z = zeros(size(coh6, 1), 3);
coh_hexa_z(<span class="org-type">:</span>, 1) = coh6(<span class="org-type">:</span>, 2); <span class="org-comment">% marble_z</span>
coh_hexa_z(<span class="org-type">:</span>, 2) = coh6(<span class="org-type">:</span>, 3); <span class="org-comment">% tilt_z</span>
coh_hexa_z(<span class="org-type">:</span>, 3) = coh6(<span class="org-type">:</span>, 4); <span class="org-comment">% hexa_z</span>
</pre>
</div>
</div>
</div>
<div id="outline-container-orged9d5af" class="outline-3">
<h3 id="orged9d5af"><span class="section-number-3">5.2</span> X-direction FRF</h3>
<div class="outline-text-3" id="text-5-2">
<div id="orge7f979c" class="figure">
<p><img src="figs/marble_x_frf.png" alt="marble_x_frf.png" />
</p>
<p><span class="figure-number">Figure 1: </span>Response to a force applied on the marble in the X direction</p>
</div>
<div id="orgaa49b69" class="figure">
<p><img src="figs/hexa_x_frf.png" alt="hexa_x_frf.png" />
</p>
<p><span class="figure-number">Figure 2: </span>Response to a force applied on the hexa in the X direction</p>
</div>
</div>
</div>
<div id="outline-container-orgc5bca15" class="outline-3">
<h3 id="orgc5bca15"><span class="section-number-3">5.3</span> Y-direction FRF</h3>
<div class="outline-text-3" id="text-5-3">
<div id="orgb8bc82d" class="figure">
<p><img src="figs/marble_y_frf.png" alt="marble_y_frf.png" />
</p>
<p><span class="figure-number">Figure 3: </span>Response to a force applied on the marble in the Y direction</p>
</div>
<div id="orgab0bae7" class="figure">
<p><img src="figs/hexa_y_frf.png" alt="hexa_y_frf.png" />
</p>
<p><span class="figure-number">Figure 4: </span>Response to a force applied on the hexa in the Y direction</p>
</div>
</div>
</div>
<div id="outline-container-org281b6fd" class="outline-3">
<h3 id="org281b6fd"><span class="section-number-3">5.4</span> Z-direction FRF</h3>
<div class="outline-text-3" id="text-5-4">
<div id="orgfeeae0c" class="figure">
<p><img src="figs/marble_z_frf.png" alt="marble_z_frf.png" />
</p>
<p><span class="figure-number">Figure 5: </span>Response to a force applied on the marble in the Z direction</p>
</div>
<div id="org1d0823f" class="figure">
<p><img src="figs/hexa_z_frf.png" alt="hexa_z_frf.png" />
</p>
<p><span class="figure-number">Figure 6: </span>Response to a force applied on the hexa in the Z direction</p>
</div>
</div>
</div>
<div id="outline-container-org79b392d" class="outline-3">
<h3 id="org79b392d"><span class="section-number-3">5.5</span> Save the processed data</h3>
<div class="outline-text-3" id="text-5-5">
<p>
Finally, we save the processed data.
</p>
<div class="org-src-container">
<pre class="src src-matlab">save(<span class="org-string">'./data/id31_microstation_2018_01_12_frf.mat'</span>, ...
<span class="org-string">'freq_frf'</span>, ...
<span class="org-string">'frf_marble_x'</span>, ...
<span class="org-string">'frf_marble_y'</span>, ...
<span class="org-string">'frf_marble_z'</span>, ...
<span class="org-string">'frf_hexa_x'</span>, ...
<span class="org-string">'frf_hexa_y'</span>, ...
<span class="org-string">'frf_hexa_z'</span>);
save(<span class="org-string">'./data/id31_microstation_2018_01_12_coh.mat'</span>, ...
<span class="org-string">'freq_frf'</span>, ...
<span class="org-string">'coh_marble_x'</span>, ...
<span class="org-string">'coh_marble_y'</span>, ...
<span class="org-string">'coh_marble_z'</span>, ...
<span class="org-string">'coh_hexa_x'</span>, ...
<span class="org-string">'coh_hexa_y'</span>, ...
<span class="org-string">'coh_hexa_z'</span>);
</pre>
</div>
</div>
</div>
</div>
<div id="outline-container-orgfbc6e27" class="outline-2">
<h2 id="orgfbc6e27"><span class="section-number-2">6</span> Results</h2>
<div class="outline-text-2" id="text-6">
<div class="important" id="orgbc7d1c6">
<ul class="org-ul">
<li>Resonances at 42Hz, 70Hz and 125Hz have been identified</li>
<li>The coherence is much better than when using accelerometers</li>
</ul>
</div>
</div>
</div>
</div>
<div id="postamble" class="status">
<p class="author">Author: Dehaeze Thomas</p>
<p class="date">Created: 2020-11-12 jeu. 10:26</p>
</div>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink