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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>Minimum or Maximum Member Size</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">
Use the maximum and minimum member size restrictions to prevent parts of the model from becoming too thick or too thin.
</span>

</p>

</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 shape optimization." href = "../TsoCmdMap/tso-r-cmd-dvconShape.htm#tso-r-cmd-dvconShape">DVCON_SHAPE</a></td></tr></table></td></tr></table>




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<p>
<table class = "table" id = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96"><caption/><colgroup><col style = "width:33.33333333333333%"/><col style = "width:33.33333333333333%"/><col style = "width:33.33333333333333%"/></colgroup><thead class = "thead">
<tr class = "row">
<th class = "entry" id = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__1">Applicable for</th>
<th class = "entry align-center" id = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__2">Controller (SHAPE_CONTROLLER)</th>
<th class = "entry align-center" id = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__3">Sensitivity (SHAPE_SENSITIVITY)</th>
</tr>
</thead><tbody class = "tbody">
<tr class = "row">
<td class = "entry" headers = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__1">CHECK_MAX_MEM</td>
<td class = "entry align-center" headers = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__2">OK</td>
<td class = "entry align-center" headers = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__3">-</td>
</tr>
<tr class = "row">
<td class = "entry" headers = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__1">CHECK_MAX_MEM</td>
<td class = "entry align-center" headers = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__2">OK</td>
<td class = "entry align-center" headers = "tso-c-usr-shape-desArea-dvcMem__table_0575E86A59E14DAF971CDF763C24CC96__entry__3">-</td>
</tr>
</tbody></table>
</p>

<p>For the definition of minimum member size a radius is specified, such that normal to the surface
   of the model a minimum thickness of 2*radius must be achieved. If optimization displacements
   break this restriction, they will be readapted according to the selected main criterion. If the
   structure is smaller in certain regions from the very first, only growth is permitted in these
   areas unless the areas fit the condition. <code class = "ph codeph">CHECK_MAX_MEM</code> works analogously. </p>
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<td class = "entry">
<br/><img class = "image" id = "tso-c-usr-shape-desArea-dvcMem__image_754C1799744A48AC830375FD5354D484" src = "../TsoUserImages/ae038944.jpg" width = "450"/><br/>
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<p>A typical parameter set for the member size restriction is of the
following form:</p>
<pre class = "codeblock">
<code class = "ph codeph">
DVCON_SHAPE
 ID_NAME       = ...
 ND_GROUP      = &lt;member_size_nodes&gt;
 CHECK_MAX_MEM = &lt;member_size_radius&gt;
 CHECK_MIN_MEM = &lt;member_size_radius&gt;
 CHECK_NDGR    = &lt;member_size_check_group&gt;
 TOLERANCE     = &lt;tolerance_for_intersection_tests&gt;
END_
</code>
</pre>
<p>Technically the implementation is based on the surface of the finite elements of the design
   nodes. The member size is calculated as the distance between a node and the intersection point in
   the negative normal direction to an element surface. If no element surface is intersected, the
   member size is ignored for this node.</p>
<p>The <code class = "ph codeph">ND_GROUP</code> parameter specifies the node group that
is modified by the algorithm. This group should be a subset of the mesh smooth
area. The distance of the nodes in this group is tested against the
node group specified by <code class = "ph codeph">CHECK_NDGR</code>. This is an optional
parameter and set by default to <code class = "ph codeph">&lt;MEMBER_SIZE_NODES&gt;</code>.
This option is useful if the member size shall only be tested against
certain regions like shown in the following figure.</p>
<p>The <code class = "ph codeph">TOLERANCE</code> parameter is important for intersection
tests: If  the intersection test for one node misses the border of
the <code class = "ph codeph">&lt;MEMBER_SIZE_CHECK_GROUP&gt;</code> slightly, the
element faces can be extended by the <code class = "ph codeph">TOLERANCE</code> value
(in absolute units) so that the intersection test succeeds and the desired
member size for this node is not ignored. However a too large <code class = "ph codeph">TOLERANCE</code>
value implies the risk of getting incorrect distances. This parameter
is optional and the default value is 0.1 * max element length.</p>
<table class = "table" id = "tso-c-usr-shape-desArea-dvcMem__ae296258"><caption/><colgroup><col/></colgroup><tbody class = "tbody">
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<td class = "entry">
<br/><img class = "image" id = "tso-c-usr-shape-desArea-dvcMem__image_3B4F04FB122F4C8983421465D4346F58" src = "../TsoUserImages/ae048545.jpg" width = "450"/><br/>
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<div class = "note collapse"><span class = "run-in.note">Note:
    		</span><span class = "notecontent"><p><ul class = "ul" id = "tso-c-usr-shape-desArea-dvcMem__ul_810FBB58D8E44CE6825085C30A872632">
<li class = "li">
If your initial model does not fulfill your desired member size, the
member size restriction is unable to fit the model to these values.
</li>
<li class = "li"> If you want to ensure the minimum (maximum) member
      size restriction for a certain region that is not necessarily part of the mesh smooth area,
      choose all surface nodes of this region as <code class = "ph codeph">CHECK_NDGR</code>. Areas that already
      fulfill your restriction and are not influenced by the optimization can be left out. </li>
<li class = "li"> The minimum member size restriction tends to be
      nonconservative. This means that the resulting member size is possibly smaller than the
      desired one. A workaround is to give a higher desired minimum member size value. </li>
<li class = "li">For the same reason, the maximum member size tends to be conservative.</li>

<li class = "li">The member size restrictions are not yet available for sensitivity-based shape optimization.</li>
</ul></p></span></div>


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