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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 Loading Displacement Restrictions</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">When the model is loaded with the <code class = "ph codeph">FEM_INPUT</code> command all existing nodes,
      elements, material properties, coordinate systems, and essential element properties are read
      from the FE input file.</span>

</p>
<ul><li><a href = "#tso-c-usr-model-displRestrLoad__tso-c-usr-model-displRestrLoad-rmk" id = "toc_rg" title = "">Remarks</a></li></ul>
</p></td></tr></table></td><td class = "DocHeader2"><table class = "DocTopicsSeeAlso" id = "table13"><tr><td class = "TopicsTitle">See Also</td></tr></table><table class = "DocTopicsInOtherGuides" id = "table14"><tr><td height = "8px"/></tr><tr><td class = "TopicsTitleNormal">In Other Guides</td></tr><tr><td><a title = "Determines the attributes (nodal boundary conditions) of the FE model that should be loaded in TOSCA_PREP and TOSCA_OPT and which other actions should be considered during loading (for example, automatic determination of the surface nodes). This command must be defined before the FEM_INPUT command in the parameter file to be known during model import." href = "../TsoCmdMap/tso-r-cmd-options.htm#tso-r-cmd-options">OPTIONS</a></td></tr></table></td></tr></table>




<div class = "body conbody">
<p>Forces, pressures, and other loads are not required by the optimization model and therefore not
      loaded. By default, fixed nodes are not loaded. Using the <code class = "ph codeph">READ_BC = ALL</code>
      option in the command <code class = "ph codeph"><a class = "xref" href = "../TsoCmdMap/tso-r-cmd-options.htm" title = "Determines the attributes (nodal boundary conditions) of the FE model that should be loaded in TOSCA_PREP and TOSCA_OPT and which other actions should be considered during loading (for example, automatic determination of the surface nodes). This command must be defined before the FEM_INPUT command in the parameter file to be known during model import.">OPTIONS</a></code>, all fixed nodes
      are loaded directly as node displacement restrictions for the optimization model. This option
      is activated with the command:</p>
<pre class = "codeblock">
<code class = "ph codeph">OPTIONS
</code><code class = "ph codeph"> READ_BC = ALL
</code><code class = "ph codeph">END_
</code></pre>
<div class = "section" id = "tso-c-usr-model-displRestrLoad__tso-c-usr-model-displRestrLoad-rmk"><h2 class = "title sectiontitle">Remarks</h2>

<ol class = "ol" id = "tso-c-usr-model-displRestrLoad__ol_11B5F6617AD14BEA9457E55342457A13">
<li class = "li">For some solver interfaces it is also possible to directly enter a number
to specify which fixed nodes are loaded as optimization boundary conditions.
This proves especially useful when the optimization boundary conditions
are defined as an additional <span class = "ph">load case</span>
in the FE model. The exact function of this load option depends on the
different interfaces (see <a class = "xref" href = "tso-m-usr-solver-sb.htm#tso-m-usr-solver-sb" title = "This chapter describes the formats and functionalities of the different solvers supported by SIMULIA Tosca Structure. The topological and physical properties of the analysis model (finite element input file) are required for the optimization of an FE model. Normally, not all information contained in the analysis model is necessary for an optimization. The optimization module returns the modified model data to the FE solver. The node coordinates are changed during shape and bead optimization. New materials and element properties are generated during topology optimization and the assignments of the elements to the material definitions and material properties are changed. Therefore, there are very few restrictions to the FE modeling (finite element input file).">Solver Specific Features</a>).</li>
<li class = "li">Fixed nodes can also be defined in the parameter file with the command
<code class = "ph codeph">DVCON_SHAPE</code>. However, defining fixed nodes in the FE
model is more efficient.</li>
<li class = "li">Only fixed nodes with a translation equal to zero in
          the one, two, or three direction according to the coordinate systems of the nodes can be
          loaded from the FE input in the optimization model. Constraint displacements not equal to
          zero are not loaded.</li>
</ol>
</div>

</div>

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