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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> Constraining an Eigenfrequency </h1></td></tr><tr><td class = "DocHeader4" colspan = "2"/></tr><tr><td class = "DocHeader3" colspan = "2"><table class = "DocThemeIntro" id = "table12"><tr><td class = "Intro1"><p class = "header"><p class = "abstract">
<span class = "shortdesc">
You can define constraints for eigenfrequencies in the topology
optimization tasks such as stiffness optimization or minimizing the mass.
</span>

</p>
<p>This task shows you how to:
					</p><ul><li><a href = "#tso-t-user-TopOpt-ConstFR-gui" id = "toc_rg" title = "">
Define a Design Response for a Specific Eigenfrequency in <span class = "ph">Tosca Structure.gui</span>
</a></li></ul>
</p></td></tr><tr><td class = "Intro2"><hr class = "header"/><span class = "run-in-beforeyoubegin">Before you begin: </span>
<p>
This example uses the conditions that the first eigenfrequency is above 100 Hz and the
second eigenfrequency is above 250 Hz.
</p>
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<div class = "body taskbody">
<div class = "p"><!--xxx--></div>


<section><div class = "li step p">

For each condition, a separate eigenfrequency design response is to
be defined as follows:

<p>
<pre class = "codeblock">
<code class = "ph codeph">
DRESP
 ID_NAME    = eigenfrequency_1
 DEF_TYPE   = SYSTEM
 TYPE       = DYN_FREQ
 LC_SET     = MODAL, ALL, 1
END_

DRESP
 ID_NAME    = eigenfrequency_2
 DEF_TYPE   = SYSTEM
 TYPE       = DYN_FREQ
 LC_SET     = MODAL, ALL, 2
END_

CONSTRAINT
 ID_NAME    = con_eigen_1
 DRESP      = eigenfrequency_1
 MAGNITUDE  = ABS
 GE_VALUE   = 100.0
END_

CONSTRAINT
 ID_NAME    = con_eigen_2
 DRESP      = eigenfrequency_2
 MAGNITUDE  = ABS
 GE_VALUE   = 150.0
END_

OPTIMIZE
 ...
 CONSTRAINT = con_eigen_1
 CONSTRAINT = con_eigen_2
 ...
END_
</code>
</pre>
</p>
</div></section>
</div>


<article class = "topic task nested1" aria-labelledby = "ariaid-title2" id = "tso-t-user-TopOpt-ConstFR-gui">
<h2 class = "title topictitle2">
Define a Design Response for a Specific Eigenfrequency in <span class = "ph">Tosca Structure.gui</span>
</h2>

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

To create a new Design Response, choose <span class = "ph uicontrol">Command &gt; Design Response</span>.

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

Set <span class = "ph uicontrol">DefType = System</span>,
<span class = "ph uicontrol">Category = Base</span> and <span class = "ph uicontrol">Type = DYN_FREQ</span>.

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

To choose the <span class = "ph">load cases</span>, press <span class = "ph uicontrol">Add LC</span> and set <span class = "ph uicontrol">Analysis Type</span> to <span class = "ph uicontrol">MODAL</span>,
enter  the <span class = "ph">load case</span>
ID and the numbers of eigenmodes (for example, 1) in the <span class = "ph uicontrol">Eigenmode/Subcase</span>
field.<br/><img class = "image" src = "../TsoUserImages/topo_dresp_eigenfreq_dialog_6.png" width = "450"/><br/>

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

</article>


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