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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>About Member Size Control</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"> The maximum and minimum member size restrictions prevent parts of the model from becoming too thick or too thin.</span>

</p>
<p>This page discusses: </p><ul><li><a href = "#tso-c-user-TopOpt-DesArea-MemberSizeContr-Min" id = "toc_rg" title = "Thin trusses in the resulting structure are often undesirable, depending on the manufacturing process. Defining a minimum thickness avoids the creation of small substructures in the final result.">Minimum Member Size Control</a></li><li><a href = "#tso-c-user-TopOpt-DesArea-MemberSizeContr-Max" id = "toc_rg" title = "The definition of a maximum truss thickness is often required to design castable components. With this restriction, thick parts are avoided by splitting them into several thinner parts.">Maximum Member Size Control</a></li></ul>
</p></td></tr></table></td><td class = "DocHeader2"><table class = "DocTopicsSeeAlso" id = "table13"><tr><td class = "TopicsTitle">See Also</td></tr><tr><td><a title = "You can define a maximum truss thickness to design castable components. This restriction avoids thick parts are avoided by splitting them into several thinner parts." href = "tso-t-user-TopOpt-DesArea-MaxMS.htm#tso-t-user-TopOpt-DesArea-MaxMS">Defining a Maximum Truss Thickness (Maximum Member Size)</a></td></tr><tr><td><a title = "Thin trusses in the resulting structure are often undesirable, depending on the manufacturing process. You can define a minimum truss thickness to avoid the creation of small substructures in the final result." href = "tso-t-user-TopOpt-DesArea-MinMS.htm#tso-t-user-TopOpt-DesArea-MinMS">Defining a Minimum Truss Thickness (Minimum Member Size)</a></td></tr></table></td></tr></table>




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<article class = "topic concept nested1" aria-labelledby = "ariaid-title2" id = "tso-c-user-TopOpt-DesArea-MemberSizeContr-Min">
<h2 class = "title topictitle2">Minimum Member Size Control</h2>


<div class = "body conbody"><p class = "shortdesc">Thin trusses in the resulting structure are often undesirable,
depending on the manufacturing process. Defining a minimum
thickness avoids the creation of small substructures in the final
result.
</p>

<p>The minimum member size control feature ensures the mesh independence of the results. A coarse
mesh and a fine mesh lead to the same optimized topology if the minimum member sizes for both cases
are set to the same absolute size. <div class = "note"><span class = "run-in.note">Note:
			</span><span class = "notecontent">In both cases, the size must be larger than the average
element edge length. </span></div>
</p>
<p>Optimized engine support with and without MINIMUM member size restriction is presented in the following figure:</p>
<table class = "table" id = "tso-c-user-TopOpt-DesArea-MemberSizeContr-Min__ag617216"><caption/><colgroup><col/></colgroup><tbody class = "tbody">
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<td class = "entry"><br/><img class = "image" id = "tso-c-user-TopOpt-DesArea-MemberSizeContr-Min__image_9559B2E373DD419F8EE84CE9BD7FE84F" src = "../TsoUserImages/ag096b11.jpg" width = "450"/><br/></td>
</tr>
</tbody></table>

<div class = "note"><span class = "run-in.note">Note:
			</span><span class = "notecontent"><p><ul class = "ul" id = "tso-c-user-TopOpt-DesArea-MemberSizeContr-Min__ul_9636A1DF13534D0CB876E03991735984">
<li class = "li">It is impossible to ensure the accurate minimum
thickness of the structures. For some cases, the results contain parts with a diameter smaller than
the defined minimum member size. </li>
<li class = "li">The CPU-time for the calculation increases
quadratically with the minimum member size. To save calculation time, the recommendation is to only
define the restriction in areas of the model where thin parts must be avoided. To identify these
areas, the first step is to perform an optimization without restrictions.</li>
</ul></p></span></div>

</div>

</article>
  
<article class = "topic concept nested1" aria-labelledby = "ariaid-title3" id = "tso-c-user-TopOpt-DesArea-MemberSizeContr-Max">
<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">Maximum Member Size Control</h2>


<div class = "body conbody"><p class = "shortdesc">The definition of a maximum truss thickness is often required to design castable
components. With this restriction, thick parts are avoided by splitting them into several thinner
parts. </p>

<p>Normally, the maximum member size control is also a minimum member
size control. In the restriction area, the resulting structure contains
trusses mainly of the given defined diameter. Generally, no thinner trusses
exist. Usually, the combination of a maximum member size control and
a minimum member size control is not required.</p>
<p>The following figure shows 
a plate designed with and without maximum member size control:</p>
<p><br/><img border = "1" class = "image" id = "tso-c-user-TopOpt-DesArea-MemberSizeContr-Max__image_08F28627DDDC437A8397DBB3B756448D" src = "../TsoUserImages/ag096c5b.jpg" width = "450"/><br/></p>
<p>There are different algorithms for the maximum member size feature implemented, where both result in distinct optimization 
   results. While the default <code class = "ph codeph">METHOD = FILTER</code> obtains clearer results, <code class = "ph codeph">METHOD = LOCAL_VOLUME</code> tends to
   be more robust in terms of optimization convergence 
   (see <a class = "xref" href = "../TsoExampleMap/tso-t-example-topo-plateSetMinMaxMember.htm#tso-t-example-topo-plateSetMinMaxMember" title = "To control the thickness of a model, either define a minimum member size control or a maximum member size control. The specified thickness must be at least twice the average element edge length. Undesirable conditions might appear for smaller values.">Defining a Thickness Control for the Plate Model</a>).
</p>
</div>

</article>

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