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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>Overview of Thermal Design Responses</h1></td></tr><tr><td class = "DocHeader4" colspan = "2"/></tr><tr><td class = "DocHeader3" colspan = "2"><table class = "DocThemeIntro" id = "table12"><tr><td class = "Intro1Only"><p class = "header"><p class = "abstract">
<span class = "shortdesc">This section describes the theory of thermal design responses. They are available only with 
           <span class = "ph">Abaqus</span> in combination with
           <span class = "ph">Tosca</span> sensitivities . </span>

</p>
<p>This page discusses: </p><ul><li><a href = "#tso-c-usr-terms-thermal-Ovw__tso-c-usr-terms-thermal-temp-anaType" id = "toc_rg" title = ""><span class = "ph">Analysis Types: Thermal Analysis</span></a></li><li><a href = "#tso-c-usr-terms-thermal-Ovw__tso-c-usr-terms-tempExpl-paraFile" id = "toc_rg" title = ""><span class = "ph">Command in Parameter File</span></a></li><li><a href = "#tso-c-usr-terms-thermal-Ovw__tso-c-usr-terms-thermal-rmk" id = "toc_rg" title = ""><span class = "ph">Remarks:</span></a></li></ul>
</p></td></tr></table></td></tr></table>




<div class = "body conbody">

<div class = "section" id = "tso-c-usr-terms-thermal-Ovw__tso-c-usr-terms-thermal-temp-anaType"><h2 class = "title sectiontitle"><span class = "ph">Analysis Types: Thermal Analysis</span></h2>

<p>For optimization based on thermal results temperature (defined using nodes), reaction
flux (defined using nodes) and internal flux (defined using nodes and
elements) is available for objectives and constraints. Those design responses can be used for
conduction or convection loadcases. Radiation is not supported.</p>
<p>You can also setup a static-thermal optimization by referencing multiple inputs decks, 
one with the thermal and one with the static loadcase: </p>
<pre class = "codeblock">
<code class = "ph codeph">
FEM_INPUT
  ID_NAME = MY_INPUT_FILES
  FILE    = topo_thermal.inp
  FILE    = topo_static.inp
END_
</code>
</pre>
<p>But please note, that coupled analysis is not allowed.</p>

<p><span class = "ph">Tosca Structure</span>
supports different heat transfer mechanisms defined as material parameters
or boundary conditions.</p>
	
<p>Updating the convection during topology optimization
iteration history: The convection is automatically updated during the
topology optimization iterations as the surface is changing when elemental
material is added and removed. However, the user has the possibility
to enforce that the convection in the original model should be kept
during the topology optimization iterations. By default, the convection
is only updated when a thermal design response is also included
in the optimization formulation (<code class = "ph codeph">OPTIMIZE</code>). Nevertheless,
the user can enforce that the convection is always updated during the
optimization iterations. The user can control the update of the convection
using the command block <code class = "ph codeph">OPT_PARAM</code>, item <code class = "ph codeph">UPDATE_CONVECTION</code>:</p>
<ol class = "ol">
<li class = "li"><code class = "ph codeph">THERMAL_OPT</code>: The convection
is modified modified to include new surfaces generated during the 
optimization only if a thermal design response
is included in the optimization formulation (<code class = "ph codeph">OPTIMIZE</code>).</li>
<li class = "li"><code class = "ph codeph">EVER</code>: The convection is always
modified to include new surfaces generated during the optimization.</li>
<li class = "li"><code class = "ph codeph">NEVER</code>: The convection is not
modified during the optimization iterations. Therefore, the original convection
is kept and used for all iterations during the optimization.</li>
</ol>
</div>


<div class = "section" id = "tso-c-usr-terms-thermal-Ovw__tso-c-usr-terms-tempExpl-paraFile"><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 sectiontitle"><span class = "ph">Command in Parameter File</span></h2>


<p>The design responses (<code class = "ph codeph">DRESP</code>)
for thermal are defined in the following way:</p>
<pre class = "codeblock">
<code class = "ph codeph">
DRESP
 ID_NAME    = ...
 TYPE       = ...
 DEF_TYPE   = SYSTEM  (DRESP for internal force)
 GROUP_OPER = MAX or SUM
 ND_GROUP   = ...   (insert the element group)
 EL_GROUP   = ...   (insert the node group, only required for INTERNAL_HFLUX)
END_
</code>
</pre>
<p><code class = "ph codeph">INTERNAL_HFLUX</code> is defined by nodes and elements
as shown in the figure below.</p>
<br/><img class = "image" src = "../TsoUserImages/thermal_node_el_group.png" width = "446" height = "169"/><br/>

</div>


<div class = "section" id = "tso-c-usr-terms-thermal-Ovw__tso-c-usr-terms-thermal-rmk"><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 sectiontitle"><span class = "ph">Remarks:</span></h2>

<ol class = "ol">
<li class = "li">In <span class = "ph">Abaqus</span>,
conduction is defined using the material card 
<pre class = "codeblock">
*Material, name=
*Conductivity
</pre>
Note that identical material cards are required in both structural
and thermal finite element input file, respectively. </li>
<li class = "li">In <span class = "ph">Abaqus</span>,
convection is defined using the option
<pre class = "codeblock">
*Sfilm
</pre></li>
<li class = "li">In <span class = "ph">Abaqus</span>,
only DC3xx elements are supported. The thermal elements DC3xx correspond
to C3xx elements in the correlating static analysis file with the same
number and some node numbers.</li>
<li class = "li">Thermal elements with linear interpolations are
to be preferred. Thermal elements with higher-order interpolations can
cause instabilities for the analysis. </li>
<li class = "li">Good topology optimization results require a fine mesh. </li>
</ol>
</div>

</div>

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