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      <title>CTRIA6</title>
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      <div class="title_refTopic" id="xps10_pagetitle">CTRIA6 </div>
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      <h4 class="refClassification">Curved Triangular Shell Element Connection </h4>
      <p class="para_refTopic">Defines a curved triangular shell element or plane strain with six grid points. </p>
      <div class="title_refCategory">Format: </div>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
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                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">1 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">2 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">3 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">4 </p>
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                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">5 </p>
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                     <p class="para_th">6 </p>
                  </th>
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                     <p class="para_th">7 </p>
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                     <p class="para_th">8 </p>
                  </th>
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                     <p class="para_th">9 </p>
                  </th>
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                     <p class="para_th">10 </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CTRIA6 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">EID </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">PID </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">G1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">G2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">G3 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">G4 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">G5 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">G6 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">THETA or MCID </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">ZOFFS </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">T1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">T2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">T3 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TFLAG </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
               </tr>
            </tbody>
         </table><br></div>
      <div class="title_refCategory">Example: </div>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
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            <tbody>
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                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CTRIA6 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">302 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">3 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">31 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">33 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">71 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">32 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">51 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">52 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">45 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">.03 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">.020 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">.025 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">.025 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
               </tr>
            </tbody>
         </table><br></div>
      <div class="title_refCategory">Fields:</div>
      <div class="refCategoryContent">
         <table cellpadding="9" width="100%" align="center">
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               <col span="1" width="84*">
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            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th"><b class="uiTerm">Field </b></p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th"><b class="uiTerm">Contents </b></p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Element Identification number.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">PID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Property identification number of PSHELL, PCOMP, or PLPLANE entry.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">G1, G2, G3 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Identification numbers of connected corner grid points.  (Unique Integers &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">G4, G5, G6 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Identification number of connected edge grid points.  Optional data for any or all three points.  (Integer &ge; 0 or blank) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">THETA </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material property orientation angle in degrees.  THETA is ignored for hyperelastic elements.  (Real; Default = 0.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MCID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material coordinate system identification number.  The x-axis of the material coordinate system is determined by projecting the x-axis of the MCID coordinate system (defined by the CORDij entry or zero for the basic coordinate system) onto the surface of the element.  MCID is ignored for hyperelastic elements.  (Integer &ge; 0; if blank, then THETA = 0.0 is assumed.) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref92666"></a><div class="figure">
            <p align="center"><img align="bottom" src="graphics/bulkc2-fig32.gif"></p>
         </div>
         <div class="title_figure">Figure. MCID Coordinate System Definition </div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="16*">
               <col span="1" width="84*">
            </colgroup>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ZOFFS </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Offset from the surface of grid points to the element reference plane; see Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_34.html#ref91490');return(false);">56-6.</a> ZOFFS is ignored for hyperelastic elements. (Real) 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TFLAG </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Integer Flag which specifies how Ti is used to define membrane thickness of element. (0, 1, or blank) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Ti </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Membrane thickness of element at grid points G1 through G4 if TFLAG=0 or blank. If TFLAG=1, membrane thickness becomes a product of Ti and the thickness on the PSHELL card. Ti is ignored for hyperelastic elements.  (Real &ge; 0.0 or blank, not all zero.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_34.html#ref82374b');return(false);">56-4</a> for default.) 
                     </p>
                  </td>
               </tr>
            </tbody>
         </table><br></div>
      <div class="title_refCategory">Remarks: </div>
      <div class="refCategoryContent">
         <ol type="1" start="1">
            <li>
               <p class="para_item">Element identification numbers should be unique with respect to all other element IDs. </p>
            </li>
            <li>
               <p class="para_item">Grid points G1 through G6 must be numbered as shown in <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_34.html#ref19636');return(false);">Figure 13-</a>. 
               </p>
            </li>
            <li>
               <p class="para_item">The orientation of the material property coordinate system is defined locally at each interior integration point by THETA, which is the angle between x<sub class="subscript">material</sub> and the line of constant &eta;. 
               </p>
            </li>
            <li><a name="ref82374b"></a><p class="para_item">T1, T2, and T3 are optional.  If not supplied, they will be set equal to the value of T on the PSHELL entry. </p>
            </li>
            <li>
               <p class="para_item">It is recommended that the midside grid points be located within the middle third of the edge. </p>
            </li>
            <li><a name="ref91490"></a><p class="para_item">Elements may be offset from the connection points by means of the ZOFFS field.  Other data, such as material matrices and stress fiber locations, are given relative to the reference plane.  A positive value of ZOFFS implies that the element reference plane is offset a distance of ZOFFS along the positive z-axis of the element coordinate system.  If the ZOFFS field is used, then both the MID1 and MID2 fields must be specified on the PSHELL entry referenced by PID. </p>
               <p class="para_item">The specification of offset vectors gives erroneous results in solution sequences with linear buckling analysis, SOLs 5, 16, 105 and 200. </p>
            </li>
            <li>
               <p class="para_item">If all midside grid points are deleted, then the element will be excessively stiff and the transverse shear forces will be incorrect.  A User Warning Message is printed.  A CTRIA3 element entry is recommended instead.  If the element is hyperelastic, then the element is processed identically to the hyperelastic CTRIA3 element. </p>
            </li>
            <li>
               <p class="para_item">For a description of the element coordinate system, see <a class="links" href="javascript:void(0)" onclick="top.popUpPage('QRG/linkInter_target_not_resolved.html#element:ref55634:-aux,-home','linkInter','menubar=yes,status=yes,resizable=yes,toolbar=yes,scrollbars=yes,location=no,directories=no');return(false);">&ldquo;Plate and Shell Elements&rdquo; </a>in the <em>NX Nastran Element Library</em>.  Stresses and strains are output in the local coordinate system identified by <em>x<sub class="subscript">l</sub></em> and<em>y<sub class="subscript">l</sub></em>  in <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_34.html#ref19636');return(false);">Figure 13-</a>.  For hyperelastic elements, stresses and strains are output in the coordinate system defined by the CID field on the PLPLANE entry. 
               </p><a name="ref19636"></a><div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-fig33.gif"></p>
               </div>
               <div class="title_figure">Figure. CTRIA6 Element Geometry and Coordinate Systems </div>
            </li>
            <li>
               <p class="para_item">For hyperelastic elements, the plot codes are specified under the CTRIAFD element name in <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/09ref75809_1.html');return(false);">&ldquo;Item Codes&rdquo;</a>. 
               </p>
            </li>
         </ol>
      </div>
      <div class="title_refCategory">Remarks related to SOL 601: </div>
      <div class="refCategoryContent">
         <ol type="1" start="1">
            <li>
               <p class="para_item">Only elements with 3 or 6 grid points are allowed. </p>
            </li>
            <li>
               <p class="para_item">ZOFFS is ignored. </p>
            </li>
            <li>
               <p class="para_item">When used as a plane strain element, ELCV=1 in the NXSTRAT entry will convert a 6-node triangular element to a 7-node triangular element (with 1 additional node at the centroid of the element). </p>
            </li>
         </ol>
      </div>
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