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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>Remarks for Sensitivity-Based Optimizations</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">Within this section, some remarks concerning sensitivity-based optimization are summarized.</span>

</p>
<p>This page discusses: </p><ul><li><a href = "#tso-c-usr-solver-mscNastran-remSensBasedOpt__tso-c-usr-solver-mscNastran-remSensBasedOpt-accel" id = "toc_rg" title = ""><span class = "ph">Prescribed Accelerations for Sensitivity-Based Optimization Using 
<span class = "ph">Tosca</span> Response Values and Sensitivities</span></a></li><li><a href = "#tso-c-usr-solver-mscNastran-remSensBasedOpt__tso-c-usr-solver-mscNastran-remSensBasedOpt-rem" id = "toc_rg" title = "">Remarks</a></li></ul>
</p></td></tr></table></td></tr></table>




<div class = "body conbody">
<div class = "section" id = "tso-c-usr-solver-mscNastran-remSensBasedOpt__tso-c-usr-solver-mscNastran-remSensBasedOpt-accel"><h2 class = "title sectiontitle"><span class = "ph">Prescribed Accelerations for Sensitivity-Based Optimization Using 
<span class = "ph">Tosca</span> Response Values and Sensitivities</span></h2>

<p>Prescribed acceleration loadings are often caused by gravity fields,
centrifugal loading and rotary acceleration loads. This chapter defines
which kinds of acceleration types for the <span class = "ph">MSC Nastran®</span>
are feasible for sensitivity-based topology and sizing optimization. These acceleration types are not supported for
shape and bead optimization.</p>
<p>The following commands are supported for acceleration loading:</p>
<ul class = "ul">
<li class = "li"><code class = "ph codeph">GRAV</code>: Defines acceleration vectors for gravity or other
acceleration loading.</li>
<li class = "li"><code class = "ph codeph">RFORCE</code>: Defines a static loading condition due to
an angular velocity and/or acceleration.</li>
<li class = "li"><code class = "ph codeph">ACCEL1</code>: Defines static acceleration loads at individual
<code class = "ph codeph">GRID</code> points. </li>
</ul>
<p>The following are not supported: </p>
<ul class = "ul">
<li class = "li"><code class = "ph codeph">ACCEL</code>: Defines static acceleration loads, which might vary over a region of the
                    structural model. The load variation is based on the tabular input defined on
                    this Bulk Data entry.</li>
<li class = "li"><code class = "ph codeph">DMIG,UACCEL</code>: Defines rigid body accelerations in
the basic coordinate system.</li>
</ul>
</div>


<div class = "section" id = "tso-c-usr-solver-mscNastran-remSensBasedOpt__tso-c-usr-solver-mscNastran-remSensBasedOpt-rem"><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">Remarks</h2>

<ul class = "ul">
<li class = "li"><code class = "ph codeph">ACCEL</code> and <code class = "ph codeph">ACCEL1</code> might not be available
in all versions of <span class = "ph">MSC Nastran®</span>.
</li>
<li class = "li">Default in <span class = "ph">Nastran</span>
is to apply lumped mass matrices.</li>
<li class = "li">Applying lumped mass matrices can be enforced using <code class = "ph codeph">PARAM,COUPMASS,-1</code>.</li>
<li class = "li">Applying consistent mass matrices can be enforced using <code class = "ph codeph">PARAM,COUPMASS,1</code>.</li>
<li class = "li"><span class = "ph">Tosca Structure</span>
only reads <code class = "ph codeph">PARAM,COUPMASS</code> for indicating if lumped mass
matrices or consistent mass matrices are applied. Consequently, if the
<code class = "ph codeph">METHOD</code> card for <code class = "ph codeph">RFORCE</code> is applied then
the <code class = "ph codeph">METHOD</code> card should correspond to the mass element
type chosen in <code class = "ph codeph">PARAM,COUPMASS</code>.</li>
</ul>
</div>

</div>

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