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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>Optimizing the Eigenfrequency of the Hood Model 
(<span class = "ph">Tosca Structure.gui</span>)</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"> In this example, you will follow the workflow for a standard bead optimization task with
      eigenfrequency:</span>

<ol class = "ol"><li class = "li">Define input data and design variables.</li>
    <li class = "li">Define the Constraint of the optimization task (DRESP, CONSTRAINT).</li>
    <li class = "li">Define the Objective Function (DRESP, OBJ_FUNC).</li>
    <li class = "li">Activate the Boundary Conditions (DVCON_BEAD)</li>
    <li class = "li">Define the OPTIMIZE command.</li>
    <li class = "li">(optional) Set additional settings (OPT_PARAM).</li></ol>
  </p>

</p></td></tr></table></td></tr></table>


<div class = "body taskbody">
<section><ol class = "ol steps"><li class = "li step stepexpand">
Define input data and Design Variables.
<div class = "itemgroup stepresult">
<pre class = "codeblock">
FEM_INPUT
  ID_NAME    = INPUT_FILE
  FILE       = hood_eig.inp
END_

DV_BEAD
  ID_NAME    = DESIGN_VARIABLES
  ND_GROUP   = ALL_NODES
END_
</pre>
</div>
</li><li class = "li step stepexpand">
Create a constraint for the bead height. 
<ol type = "a" class = "ol substeps">
<li class = "li substep">
Define a Design Response (DRESP):
<div class = "itemgroup stepresult">
<pre class = "codeblock">
DRESP
  ID_NAME    = dresp_bead_height
  DEF_TYPE   = SYSTEM
  ND_GROUP   = ALL_NODES
  TYPE       = BEAD_HEIGHT
  GROUP_OPER = MAX
  UPDATE     = EVER
END_
</pre>
</div>
</li>
<li class = "li substep">
Reference the Design Response in a constraint (CONSTRAINT):
<div class = "itemgroup stepresult">
<pre class = "codeblock">
CONSTRAINT
  ID_NAME    = bead_height_constraint
  DRESP      = dresp_bead_height
  MAGNITUDE  = ABS
  EQ_VALUE   = 0.5
END_
</pre>
</div>
</li>
</ol>
</li><li class = "li step stepexpand">
To define the Objective Function (OBJ_FUNC) for the first eigenfrequency, do the following:
<ol type = "a" class = "ol substeps">
<li class = "li substep">
Create a Design Response (DRESP):
<div class = "itemgroup stepresult">
<pre class = "codeblock">
DRESP
  ID_NAME    = dresp_eigenfrequency
  DEF_TYPE   = SYSTEM
  TYPE       = DYN_FREQ
  UPDATE     = EVER
  LC_SET     = MODAL,ALL,1
END_
</pre>
</div>
</li>
<li class = "li substep">
Reference the Design Response in the Objective Function (OBJ_FUNC) and maximize it:
<div class = "itemgroup stepresult">
<pre class = "codeblock">
OBJ_FUNC
  ID_NAME    = maximize_eigenfrequency
  DRESP      = dresp_eigenfrequency
  TARGET     = MAX
END_
</pre>
</div>
</li>
</ol>
</li><li class = "li step stepexpand">
Reference the Design Variables, Objective Function, and Constraints as well as DV_CONs
in the OPTIMIZE command:
<div class = "itemgroup stepresult">
<pre class = "codeblock">
OPTIMIZE
  ID_NAME    = BEAD_OPTIMIZATION
  DV         = DESIGN_VARIABLES
  OBJ_FUNC   = maximize_eigenfrequency
  CONSTRAINT = bead_height_constraint
  STRATEGY   = BEAD_CONTROLLER
END_
</pre>
</div>
</li><li class = "li step stepexpand"> 
(optional) Define the bead width and scale in the OPT_PARAM command.
<div class = "itemgroup stepresult">
<pre class = "codeblock">
OPT_PARAM
  ID_NAME    = OPT_PARAMS
  OPTIMIZE   = BEAD_OPTIMIZATION
  BEAD_WIDTH = 3.0
  SCALE      = 1.0
END

</pre>
<p>If you do not define the bead width, the system automatically determines a bead width. </p>
</div>
</li></ol></section>
<p class = "result">
The optimization result looks as follows:
<p><br/><img class = "image" src = "../TsoExampleImages/beadHoodEigConResult.png"/><br/></p>
<p>The first eigenvalue is only slightly higher 0.3140 (1.3%) after the controller-based
   optimization. The eigenvalue will NOT become higher if you change
   the number of iterations.</p>
</p>
</div>

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