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<a name = "hj-top"> </a><table class = "table1" id = "table11"><tr><td><table class = "DocHeader"><tr><td class = "DocHeader1" colspan = "2"><h1>Defining Width Control (Minimum Cluster Width)</h1></td></tr><tr><td class = "DocHeader4" colspan = "2"/></tr><tr><td class = "DocHeader3"><table class = "DocHeaderIntro" id = "table12"><tr><td class = "Intro1Only"><p class = "header"><p class = "abstract">
<span class = "shortdesc">
Small sheet parts in the resulting structure are often undesirable.
Defining a minimum sheet width (minimum cluster width) avoids the creation
of small substructures in the final result (
</span>
<code class = "ph codeph">MIN_CLUSTER_WIDTH</code>).
</p>
<p>This task shows you how to:
					</p><ul><li><a href = "#tso-t-usr-sizing-manuCond-widContr-gui" id = "toc_rg" title = "">
Define a Minimum Cluster Width in <span class = "ph">Tosca Structure.gui</span>
</a></li><li><a href = "#tso-t-usr-sizing-manuCond-widContr-parFile" id = "toc_rg" title = "">  Parameter File</a></li></ul>
</p></td></tr></table></td><td class = "DocHeader2"><table class = "DocTopicsSeeAlso" id = "table13"><tr><td class = "TopicsTitle">See Also</td></tr></table><table class = "DocTopicsInOtherGuides" id = "table14"><tr><td height = "8px"/></tr><tr><td class = "TopicsTitleNormal">In Other Guides</td></tr><tr><td><a title = "Defines restrictions of the design variables in sizing optimization." href = "../TsoCmdMap/tso-r-cmd-dvconSizing.htm#tso-r-cmd-dvconSizing">DVCON_SIZING</a></td></tr></table></td></tr></table>




<div class = "body taskbody">
<div class = "section context"><p class = "context"><span class = "run-in.context">Context: </span>
<p>
The minimum cluster width is often applied for avoiding high oscillations
in the thickness distribution and that the structure has subcomponents
with a minimum width.
</p>
<p>
In addition, the minimum cluster width for the width control can
partly circumvent the two following problems:
</p>
<ul class = "ul">
<li class = "li">
First, checkerboards might appear if one is applying a minimal value
of the lower bound of the thickness and applying lower-order shell elements
as 3 node triangular shell elements. When using higher-order shell elements
or the lower bound of the thickness is not minimal, checkerboards
are not frequent.
</li>
<li class = "li">
Secondly, a minimum cluster width ensures uniqueness of the optimization
solution independent upon the mesh size and discretization. A coarse
mesh and a fine mesh lead to the same optimized structure if the minimum
cluster widths for both cases are set to the same absolute size. Note 
that the size in both cases should be larger than the average element
edge length.
</li>
</ul>
<table class = "table" id = "tso-t-usr-sizing-manuCond-widContr__aa746553"><caption/><colgroup><col/></colgroup><tbody class = "tbody">
<tr class = "row">
<td class = "entry">
<br/><img class = "image" src = "../TsoUserImages/sizing_min_mem_large.png" width = "500" height = "42"/><br/>
</td>
</tr>
</tbody></table>
<div class = "note"><span class = "run-in.note">Note:
			</span><span class = "notecontent">
<p>
Thin sheet thickness is controlled by lower and upper bound settings
and not by the filter which controls the width.
</p>

</span></div>

</p></div>

</div>

<div class = "related-links"/>

<article class = "topic task nested1" aria-labelledby = "ariaid-title2" id = "tso-t-usr-sizing-manuCond-widContr-gui">
<h2 class = "title topictitle2">
Define a Minimum Cluster Width in <span class = "ph">Tosca Structure.gui</span>
</h2>

<div class = "body taskbody">
<section><ol class = "ol steps"><li class = "li step">

Choose <span class = "ph uicontrol">Command | DVCON_SIZING</span>  in <span class = "ph">Tosca Structure.pre</span>
screen.

</li><li class = "li step">

Apply an <span class = "ph uicontrol">ID_NAME</span> and select the
element group. If the element group is not already defined, it is necessary
to define it in advance using the <code class = "ph codeph">GROUP_DEF</code> command.

</li><li class = "li step">

Choose <span class = "ph uicontrol">Type = Minimum Cluster Width</span> and define a value:<br/><img class = "image" src = "../TsoUserImages/size_dvcon_sizing_minmember.png" width = "450"/><br/>

</li></ol></section>
</div>

</article>

<article class = "topic task nested1" aria-labelledby = "ariaid-title3" id = "tso-t-usr-sizing-manuCond-widContr-parFile">
<p><map name = "FPMap1"><area href = "#hj-top" title = "Back to Top" shape = "rect" coords = "416, 0, 435, 10"/></map><span class = "itemsprite"/></p><h2 class = "title topictitle2">  Parameter File</h2>

<div class = "body taskbody">
<section><div class = "li step p">
The resulting command looks like:
<div class = "itemgroup stepresult">
<pre class = "codeblock">
<code class = "ph codeph">
DVCON_SIZING
 ID_NAME    = &lt;Name of DVCON object&gt; 
 EL_GROUP   = &lt;Element group to be restricted&gt;
 CHECK_TYPE = MIN_CLUSTER_WIDTH
 WIDTH      = &lt;minimum width of areas of same shell thickness&gt;
END_
</code>
</pre>
</div>
</div></section>
</div>

</article>
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