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      <title>BFRlC</title>
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      <div class="title_refTopic" id="xps10_pagetitle">BFRlC </div>
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      <h4 class="refClassification">Contact Friction </h4>
      <p class="para_refTopic">Defines frictional properties between two bodies in contact. </p>
      <div class="title_refCategory">Format: </div>
      <div class="refCategoryContent">
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                     <p class="para_td">1 </p>
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                     <p class="para_td">2 </p>
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                     <p class="para_td">3 </p>
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                     <p class="para_td">4 </p>
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                     <p class="para_td">5 </p>
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                     <p class="para_td">6 </p>
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                     <p class="para_td">7 </p>
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                     <p class="para_td">8 </p>
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                     <p class="para_td">9 </p>
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                     <p class="para_td">10 </p>
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                     <p class="para_td">BFRIC </p>
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                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">FID </p>
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                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
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                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">FSTIF </p>
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                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">MU1 </p>
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                     <p class="para_td">&nbsp; </p>
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                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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                  <td align="center" bgcolor="gray" colspan="1" rowspan="1">
                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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      <div class="title_refCategory">Example:</div>
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                     <p class="para_td">BFRIC </p>
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                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">33 </p>
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                  <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">0.3 </p>
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                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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                     <p class="para_td">&nbsp; </p>
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      <div class="title_refCategory">Fields:</div>
      <div class="refCategoryContent">
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                     <p class="para_th"><b class="uiTerm">Field </b></p>
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                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th"><b class="uiTerm">Contents </b></p>
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                     <p class="para_td">FID </p>
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                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Friction identification number.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/12topic_36.html#ref22875');return(false);">34-1</a> (Integer &gt; 0).
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                     <p class="para_td">FSTlF </p>
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                     <p class="para_td">Frictional stiffness in stick.  See Remarks <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/12topic_36.html#ref37390');return(false);">34-2</a> and <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/12topic_36.html#ref98318');return(false);">34-3</a> (Real &gt; 0.0; Default=automatically selected by the program.) 
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                     <p class="para_td">MU1 </p>
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                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Coefficient of static friction.  (Real &gt; 0.0) </p>
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      <div class="title_refCategory">Remarks: </div>
      <div class="refCategoryContent">
         <ol type="1" start="1">
            <li><a name="ref22875"></a><p class="para_item">This identification number must be unique with respect to all other friction identification numbers.  This is used in the FRICID field of the BCONP Bulk Data entry. </p>
            </li>
            <li><a name="ref37390"></a><p class="para_item">The value of frictional stiffness requires care.  A method of choosing its value is to divide the expected frictional strength (MU1 * expected normal force) by a reasonable value of the relative displacement that may be allowed before slip occurs.  The relative value of displacement before slip occurs must be small compared to expected relative displacements during slip.  A large stiffness value may cause poor convergence, while too small a value may cause poor accuracy. </p>
               <p class="para_item">Frictional stiffness specified by the user is selected as the initial value.  If convergence difficulties are encountered during the analysis, the frictional stiffness may be reduced automatically to improve convergence. </p>
            </li>
            <li><a name="ref98318"></a><p class="para_item">The stiffness matrix for frictional slip is unsymmetrical.  However, the program does not use the true unsymmetrical matrix, but uses the symmetric terms instead.  This is to avoid using the unsymmetrical solver to reduce CPU time. </p>
            </li>
         </ol>
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