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      <title>NLRGAP</title>
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      <div class="title_refTopic" id="xps10_pagetitle">NLRGAP </div>
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      <h4 class="refClassification">Nonlinear Transient Load Proportional to Gap </h4>
      <p class="para_refTopic">Defines a nonlinear transient radial (circular) gap. </p>
      <div class="title_refCategory">Format: </div>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="11.14*">
               <col span="1" width="8.86*">
               <col span="1" width="10*">
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               <tr>
                  <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>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">5 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">6 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">7 </p>
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                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">8 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">9 </p>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">10 </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NLRGAP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">SID </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">GA </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">GB </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">PLANE </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TABK </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TABG </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TABU </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">RADIUS </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
                  </td>
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            </tbody>
         </table><br></div>
      <div class="title_refCategory">Example: </div>
      <div class="refCategoryContent">
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               <col span="1" width="11.08*">
               <col span="1" width="9.94*">
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               <col span="1" width="9.94*">
               <col span="1" width="9.94*">
               <col span="1" width="9.94*">
               <col span="1" width="9.94*">
               <col span="1" width="9.38*">
               <col span="1" width="9.94*">
            </colgroup>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NLRGAP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">21 </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">4 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">XY </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">10 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">6 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">1.6 </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">
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                  <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">SID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Nonlinear load set identification number.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">GA </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Inner (e.g., shaft) grid for radial gap.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">GB </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Outer (e.g., housing) grid for radial gap.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">PLANE </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Radial gap orientation plane: XY, YZ, or ZX.  (Character, Default  =  XY.) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TABK </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Table ID of gap stiffness vs. time.  (Integer &gt; 0)Table ID of gap stiffness vs. penetration.  (Integer &lt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TABG </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Table ID for radial gap clearance as function of time.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TABU </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Table ID for radial coefficient of friction as function of time.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RADIUS </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Shaft radius.  (Real &ge; 0.0, Default = 0.0) </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">NLRGAP must be selected with the Case Control command NONLINEAR = SID. </p>
            </li>
            <li>
               <p class="para_item">Multiple NLRGAP entries with the same SID are allowed. </p>
            </li>
            <li>
               <p class="para_item">The NLRGAP is not an element, but a nonlinear load similar to the NOLINi Bulk Data entries.  It computes the relative displacements of GA and GB in the selected plane and applies appropriate nonlinear loads to simulate the radial contact. </p>
            </li>
            <li>
               <p class="para_item">The degrees-of-freedom in the XY, YZ, or ZX planes (depending on the PLANE) of GA and GB must be members of the solution set.  This means the e-set for modal formulation and the d-set for direct formulation.  If RADIUS is &gt; 0.0, then the in-plane rotation degree-of-freedom must also be in the solution set. </p>
            </li>
            <li>
               <p class="para_item">As with the NOLINi entries, the NLRGAP is limited to use in direct transient response solution sequences. </p>
            </li>
            <li>
               <p class="para_item">The XY, YZ and ZX planes are relative to the displacement coordinates systems of GA and GB.  GA and GB should be coincident grids with parallel displacement coordinate systems.  NX Nastran does not check or enforce this.  Wrong answers can occur if this rule is not followed. </p>
            </li>
            <li>
               <p class="para_item">If TABK is negative, the corresponding TID on the referenced TABLEDi entry is input positive and not negative. </p>
            </li>
            <li>
               <p class="para_item">The shaft radius is used only for the computation of friction induced torque. </p>
            </li>
            <li>
               <p class="para_item">In the underlying equations, a positive coefficient of friction is consistent with counter-clockwise shaft rotation from axis 1 towards axis 2 (anti-clockwise).  A negative coefficient of friction is consistent with clockwise shaft rotation from axis 2 towards axis 1 (clockwise).  See <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/17topic_35.html#ref59492');return(false);">Figure 16-</a>. 
               </p>
            </li>
            <li>
               <p class="para_item">Nonlinear forces for the grids referenced on the NLRGAP can be output with the NLLOAD Case Control command.  See <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/17topic_35.html#ref59492');return(false);">Figure 16-</a> for the sign conventions. 
               </p><a name="ref59492"></a><div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkmno-fig05.gif"></p>
               </div>
               <div class="title_figure">Figure. Radial Gap Orientation and Nonlinear Load Sign Conventions </div>
            </li>
         </ol>
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