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      <div class="title_refTopic" id="xps10_pagetitle">PSHELL </div>
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      <h4 class="refClassification">Shell Element Property </h4>
      <p class="para_refTopic">Defines the membrane, bending, transverse shear, and coupling properties of thin shell elements. </p>
      <div class="title_refCategory">Format: </div>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
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                     <p class="para_th">1 </p>
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                     <p class="para_th">2 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">3 </p>
                  </th>
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                     <p class="para_th">4 </p>
                  </th>
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                     <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>
                  </th>
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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>
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            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">PSHELL </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">MID1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">T </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">MID2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">12I/T<sub class="subscript">**</sub>3 
                     </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">MID3 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TS/T </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">NSM </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">Z1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Z2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">MID4 </p>
                  </td>
                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
               </tr>
            </tbody>
         </table><br></div>
      <div class="title_refCategory">Example: </div>
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                     <p class="para_td">PSHELL </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">203 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">204 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">1.90 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">205 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">1.2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">206 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">0.8 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">6.32 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">+.95 </p>
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                     <p class="para_td">-.95 </p>
                  </td>
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                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
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                     <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>
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         </table><br></div>
      <div class="title_refCategory">Fields:</div>
      <div class="refCategoryContent">
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                     <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>
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            </thead>
            <tbody>
               <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.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MID1 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material identification number for the membrane.  (Integer &ge; 0 or blank) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">T </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Default membrane thickness for Ti on the connection entry.  If T is blank then the thickness must be specified for Ti on the CQUAD4, CTRIA3, CQUAD8, and CTRIA6 entries.  (Real or blank) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MID2 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material identification number for bending.  (Integer &ge; -1 or blank) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">12I/T<sub class="subscript">**</sub>3 
                     </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Bending moment of inertia ratio, 12<em>I</em>/<em>T</em><sup class="superscript">3</sup>.  Ratio of the actual bending moment inertia of the shell, <em>I</em>, to the bending moment of inertia of a homogeneous shell, <em>T</em><sup class="superscript">3</sup>/12.  The default value is for a homogeneous shell.  (Real &gt; 0.0; Default = 1.0) 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MID3 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material identification number for transverse shear.  (Integer &gt; 0 or blank; unless MID2 &gt; 0, must be blank.) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TS/T </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Transverse shear thickness ratio, <em>T<sub class="subscript">s</sub></em>/<em>T</em>.  Ratio of the shear thickness, (<em>T<sub class="subscript">s</sub></em>), to the membrane thickness of the shell, <em>T</em>.  The default value is for a homogeneous shell.  (Real &gt; 0.0; Default = .833333) 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NSM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Nonstructural mass per unit area.  (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Z1, Z2 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Fiber distances for stress calculations.  The positive direction is determined by the right-hand rule, and the order in which the grid points are listed on the connection entry.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/18topic_58.html#ref48770');return(false);">91-11. </a> for defaults.  (Real or blank) 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MID4 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material identification number for membrane-bending coupling.  See Remarks <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/18topic_58.html#ref20446');return(false);">91-6</a> and <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/18topic_58.html#ref87643');return(false);">91-13. </a> (Integer &gt; 0 or blank, must be blank unless MID1 &gt; 0 and MID2 &gt; 0, may not equal MID1 or MID2.) 
                     </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">All PSHELL property entries should have unique identification numbers with respect to all other property entries. </p>
            </li>
            <li>
               <p class="para_item">The structural mass is calculated from the density using the membrane thickness and membrane material properties. </p>
            </li>
            <li>
               <p class="para_item">The results of leaving an MID field blank (or MID2 = -1) are: </p>
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                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">MID1 </p>
                        </td>
                        <td align="left" colspan="2" rowspan="1">
                           <p class="para_td">No membrane or coupling stiffness </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">MID2 </p>
                        </td>
                        <td align="left" colspan="2" rowspan="1">
                           <p class="para_td">No bending, coupling, or transverse shear stiffness </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">MID3 </p>
                        </td>
                        <td align="left" colspan="2" rowspan="1">
                           <p class="para_td">No transverse shear flexibility </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">MID4 </p>
                        </td>
                        <td align="left" colspan="2" rowspan="1">
                           <p class="para_td">No membrane-bending coupling unless ZOFFS is specified on the connection entry.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/18topic_58.html#ref20446');return(false);">91-6. </a></p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">MID2=-1 </p>
                        </td>
                        <td align="left" colspan="2" rowspan="1">
                           <p class="para_td">See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/18topic_58.html#ref28466');return(false);">91-12. </a></p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">&nbsp; </p>
                        </td>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">Note: </p>
                        </td>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td">MID1 and MID2 must be specified if the ZOFFS field is also specified on the connection entry. </p>
                        </td>
                     </tr>
                  </tbody>
               </table><br></li>
            <li>
               <p class="para_item">The continuation entry is not required. </p>
            </li>
            <li>
               <p class="para_item">The structural damping (GE on the MATi entry) is obtained from MID1 material. </p>
            </li>
            <li><a name="ref20446"></a><p class="para_item">The following should be considered when using MID4. </p>
               <ul>
                  <li>
                     <p class="para_item">  The MID4 field should be left blank if the material properties are symmetric with respect to the middle surface of the shell.  If the element centerline is offset from the plane of the grid points but the material properties are symmetric, the preferred method for modeling the offset is by use of the ZOFFS field on the connection entry.  Although the MID4 field may be used for this purpose, it may produce ill-conditioned stiffness matrices (negative terms on factor diagonal) if done incorrectly. </p>
                  </li>
                  <li>
                     <p class="para_item">Only one of the options MID4 or ZOFFS should be used; if both methods are specified the effects are cumulative.  Since this is probably not what the user intended, unexpected answers will result.  Note that the mass properties are not modified to reflect the existence of the offset when the ZOFFS and MID4 methods are used.  If the weight or mass properties of an offset plate are to be used in an analysis, the RBAR method must be used to represent the offset.  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>. 
                     </p>
                  </li>
                  <li>
                     <p class="para_item">The effects of MID4 are not considered in the calculation of differential stiffness.  Therefore, it is recommended that MID4 be left blank in buckling analysis. </p>
                  </li>
               </ul>
            </li>
            <li>
               <p class="para_item">This entry is referenced by the CTRIA3, CTRIA6, CTRIAR, CQUAD4, CQUAD8, and CQUADR entries via PID. </p>
            </li>
            <li>
               <p class="para_item">For structural problems, MIDi must reference a MAT1, MAT2, or MAT8 material property entry </p>
            </li>
            <li>
               <p class="para_item">If the transverse shear material MID3 references a MAT2 entry, then G33 must be zero.  If MID3 references a MAT8 entry, then G1Z and G2Z must not be zero. </p>
            </li>
            <li>
               <p class="para_item">For heat transfer problems, MIDi must reference a MAT4 or MAT5 material property entry. </p>
            </li>
            <li><a name="ref48770"></a><p class="para_item">The default for Z1 is -T/2, and for Z2 is +T/2.  T is the local plate thickness defined either by T on this entry or by membrane thicknesses at connected grid points, if they are input on connection entries. </p>
            </li>
            <li><a name="ref28466"></a><p class="para_item">For plane strain analysis, set MID2=-1 and set MID1 to reference a MAT1 entry. In-plane loads applied to plain strain elements are interpreted as line-loads with a value equal to the load divided by the thickness. Thus, if a thickness of &ldquo;1.0&rdquo; is used, the value of the line-load equals the load value. Pressure can be approximated with multiple line loads where the pressure value equals the line-load dived by the length between the loads. </p>
            </li>
            <li><a name="ref87643"></a><p class="para_item">For the CQUADR and CTRIAR elements, the MID4 field should be left blank because their formulation does not include membrane-bending coupling. </p>
            </li>
            <li>
               <p class="para_item">If MIDi is greater than or equal to 10<sup class="superscript">8</sup>, then parameter NOCOMPS is set to +1 indicating that composite stress data recovery is desired.  (MIDi greater than 10<sup class="superscript">8</sup> are generated by PCOMP entries.) 
               </p>
            </li>
            <li>
               <p class="para_item">For a material nonlinear property, MID1 must reference a MATS1 entry and be the same as MID2, unless a plane strain (MID2 = -1) formulation is desired.  Also, MID3 cannot reference a MATS1 entry. </p>
            </li>
            <li>
               <p class="para_item">If transverse shear flexibility is specified for a model with curved shells where the loading is dominated by twist, results will not converge and may be inaccurate.  PARAM,SNORM should be set for this unique model condition. </p>
            </li>
         </ol>
      </div>
      <div class="title_refCategory">Remarks related to SOLs 601 and 701: </div>
      <div class="refCategoryContent">
         <ol type="1" start="1">
            <li>
               <p class="para_item">12I/T**3, MID3, TS/T, NSM, Z1, Z2, and MID4 are ignored. </p>
            </li>
            <li>
               <p class="para_item">MID1 must be specified and must be greater than 0.  MID1 is used to evaluate all material properties of the element. </p>
            </li>
            <li>
               <p class="para_item">The shell element includes membrane, bending and transverse shear effects.  Membrane and bending effects are always coupled. </p>
            </li>
            <li>
               <p class="para_item">For SOL 601, MID2 is used only to check for the condition MID2=-1 for plane strain analysis. For SOL 701, plane strain is not supported. </p>
            </li>
            <li>
               <p class="para_item">5.	By default, incompatible modes are used for 4-node shell elements in SOL 601 but not in SOL 701. The use of incompatible modes for 4-node shell elements can be set by the ICMODE parameter in NXSTRAT entry. Note that incompatible modes are not used for 4-node plane strain (i.e., MID2=-1) quadrilateral elements.</p>
            </li>
         </ol>
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