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      <title>CREEP</title>
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      <div class="title_refTopic" id="xps10_pagetitle">CREEP </div>
      <hr noshade="true">
      <h4 class="refClassification">Creep Characteristics </h4>
      <p class="para_refTopic">Defines creep characteristics based on experimental data or known empirical creep law.  This entry will be activated if a MAT1, MAT2, or MAT9 entry with the same MID is used and the NLPARM entry is prepared for creep analysis (except for SOL 601).  The creep formulation is principally suited for isotropic materials and, in general, when used with anisotropic materials may produce incorrect results.  However, slightly anisotropic materials may produce acceptable results. </p>
      <div class="title_refCategory">Format: </div>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
            <colgroup span="1">
               <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>
                  </th>
                  <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">CREEP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">MID </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">T0 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">EXP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">FORM </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TIDKP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TIDCP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">TIDCS </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">THRESH </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">TYPE </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">a </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">b </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">c </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">d </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">e </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">f </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">g </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>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
            <colgroup span="1">
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            <tbody>
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                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CREEP </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">8 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">1100. </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">CRLAW </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>
                  <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">121 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">6.985-6 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">2.444 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">7.032-4 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">0.1072 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">6.73-9 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">0.1479 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">3.0 </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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                  <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">MID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Material identification number of a MAT1, MAT2, or MAT9 entry.  (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">T0 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Reference temperature at which creep characteristics are defined.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref84553');return(false);">36-2</a> (Real; Default = 0.0). 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EXP </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Temperature-dependent term, <em>e</em><sup class="superscript">(−&Delta;<em>H</em>/(<em>R</em>·<em>T</em>0))</sup>, in the creep rate expression.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref84553');return(false);">36-2</a> (0.0 &lt; Real &le; 1.0; Default = 1.0E-9). 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">FORM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Form of the input data defining creep characteristics.  (Character:  &ldquo;CRLAW&rdquo; for empirical creep law, or &ldquo;TABLE&rdquo; for tabular input data of creep model parameters.) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TIDKP, TIDCP, TIDCS </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Identification number of a TABLES1 entry, which defines the creep model parameters <em>K<sub class="subscript">p</sub></em>(&sigma;), <em>C<sub class="subscript">p</sub></em>(&sigma;), and  <em>C<sub class="subscript">s</sub></em>(&sigma;), respectively.  See Remarks <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref65578');return(false);">36-3</a> through <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref35261');return(false);">36-5</a> (Integer &gt; 0). 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">THRESH </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Threshold limit for creep process.  Threshold stress under which creep does not occur is computed as THRESH multiplied by Young&rsquo;s modulus.  (0.0 &lt; Real &lt; 1.0E-3; Default = 1.0E-5) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TYPE </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Identification number of the empirical creep law type.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref96120');return(false);">36-1</a> (Integer:  111, 112, 121, 122, 211, 212, 221, 222, or 300). 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">a through g </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Coefficients of the empirical creep law specified in TYPE.  Continuation should not be specified if FORM = &ldquo;TABLE&rdquo;.  See Remark <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref96120');return(false);">36-1</a> (Real). 
                     </p>
                  </td>
               </tr>
            </tbody>
         </table><br></div>
      <div class="title_refCategory">Remarks: </div>
      <div class="refCategoryContent">
         <p class="para_refCategory">Two classes of empirical creep law are available: </p>
         <ul>
            <li>
               <p class="para_item">Creep Law Class 1</p>
            </li>
            <li>
               <p class="para_item">Creep Law Class 2</p>
            </li>
         </ul>
         <ol type="1" start="1">
            <li><a name="ref96120"></a><p class="para_item"><b class="uiTerm">Creep Law Class 1 </b></p>
               <p class="para_item">The first creep law class is expressed as: </p>
               <div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-equ03.gif"></p>
               </div>
               <div class="title_figure">Equation 13-1. </div>
               <p class="para_item">Parameters <em>A</em>(&sigma;), <em>R</em>(&sigma;), and <em>K</em>(&sigma;) are specified in the following form, as recommended by the Oak Ridge National Laboratory: 
               </p>
               <table border="1" cellpadding="9" width="100%" align="center">
                  <colgroup span="1">
                     <col span="1" width="22.03*">
                     <col span="1" width="29.22*">
                     <col span="1" width="11.63*">
                     <col span="1" width="22.11*">
                     <col span="1" width="11.63*">
                  </colgroup>
                  <thead>
                     <tr>
                        <th align="center" colspan="1" rowspan="1">
                           <p class="para_th"><b class="uiTerm">Parameter </b></p>
                        </th>
                        <th align="center" colspan="1" rowspan="1">
                           <p class="para_th"><b class="uiTerm">Function 1 </b></p>
                        </th>
                        <th align="center" colspan="1" rowspan="1">
                           <p class="para_th"><b class="uiTerm">Digit </b></p>
                        </th>
                        <th align="center" colspan="1" rowspan="1">
                           <p class="para_th"><b class="uiTerm">Function 2 </b></p>
                        </th>
                        <th align="center" colspan="1" rowspan="1">
                           <p class="para_th"><b class="uiTerm">Digit </b></p>
                        </th>
                     </tr>
                  </thead>
                  <tbody>
                     <tr>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">A(&sigma;) </p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">a&sigma;<sup class="superscript">b</sup></p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">i=1 </p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">a<em>e</em><sup class="superscript">b&sigma;</sup></p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">i=2 </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">R(&sigma;) </p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">c<em>e</em><sup class="superscript">d&sigma;</sup></p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">j=1 </p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">c&sigma;<sup class="superscript">d</sup></p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">j=2 </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">K(&sigma;) </p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">e · [sinh(<em>f</em>&sigma;)]<sup class="superscript">g</sup></p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">k=1 </p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">e<em>e</em><sup class="superscript">f&sigma;</sup></p>
                        </td>
                        <td align="center" colspan="1" rowspan="1">
                           <p class="para_td">k=2 </p>
                        </td>
                     </tr>
                  </tbody>
               </table><br><p class="para_item">TYPE=ijk where i, j, and k are digits equal to 1 or 2, according to the desired function in the table above.  For example, TYPE=122 defines <em>A</em>(&sigma;) = a&sigma;<sup class="superscript">b</sup>, <em>R</em>(&sigma;) = c&sigma;<sup class="superscript">d</sup>, and <em>K</em>(&sigma;) = e<em>e</em><sup class="superscript">f&sigma;</sup>. 
               </p>
               <p class="para_item"> <b class="uiTerm">Creep law Class 2</b></p>
               <p class="para_item">The second creep law class (TYPE=300) is expressed as: </p>
               <div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-equ04.gif"></p>
               </div>
               <div class="title_figure">Equation 13-2. </div>
               <p class="para_item">where the values of b and d must be defined as follows: </p>
               <p align="center"><img align="bottom" src="graphics/bulkc2-equ05.gif"></p>
               <p class="para_item">and </p>
               <p align="center"><img align="bottom" src="graphics/bulkc2-equ06.gif"></p>
               <p class="para_item">The coefficient g should be blank if TYPE = 112, 122, 222, or 212 and c, e, f, and g should be blank if TYPE = 300.  The coefficients a through g are dependent on the structural units; caution must be exercised to make these units consistent with the rest of the input data. </p>
            </li>
            <li><a name="ref84553"></a><p class="para_item">Creep law coefficients a through g are usually determined by least squares fit of experimental data, obtained under a constant temperature.  This reference temperature at which creep behavior is characterized must be specified in the T0 field if the temperature of the structure is different from this reference temperature.  The conversion of the temperature input (&deg;F or &deg;C) to &deg;K (degrees Kelvin) must be specified in the PARAM,TABS entry as follows: </p>
               <p class="para_item">PARAM,TABS,273.16 (If Celsius is used.) </p>
               <p class="para_item">PARAM,TABS,459.69 (If Fahrenheit is used.) </p>
               <p class="para_item">When the correction for the temperature effect is required, the temperature distribution must be defined in the Bulk Data entries (TEMP, TEMPP1 and/or TEMPRB), which are selected by the Case Control command TEMP(LOAD) = SID within the subcase. </p>
               <p class="para_item">From the thermodynamic consideration, the creep rate is expressed as: </p>
               <div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-equ07.gif"></p>
               </div>
               <div class="title_figure">Equation 13-3. </div>
               <p class="para_item">where: </p>
               <table cellpadding="10" width="100%" align="center">
                  <colgroup span="1">
                     <col span="1" width="86.27*">
                  </colgroup>
                  <tbody>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td"><em>H&Delta;</em> = energy of activation 
                           </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td"><em>R</em> = gas constant (= 1.98 cal/mole &deg;&Kappa;) 
                           </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td"><em>T</em> = absolute temperature (&deg;&Kappa;) 
                           </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td"><img align="bottom" src="graphics/bulkc2-ufig05.gif" border="0"> = strain/sec per activation 
                           </p>
                        </td>
                     </tr>
                  </tbody>
               </table><br><p class="para_item">If the creep characteristics are defined at temperature T0, the creep rate at temperature <em>T</em> is corrected by a factor 
               </p>
               <div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-equ08.gif"></p>
               </div>
               <div class="title_figure">Equation 13-4. </div>
               <p class="para_item">where: </p>
               <table border="" cellpadding="10" width="" align="center">
                  <colgroup span="1">
                     <col span="1" width="4919*">
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                  <tbody>
                     <tr>
                        <td align="left" colspan="1" height="74" rowspan="1" valign="top">
                           <p class="para_td"><img align="bottom" src="graphics/bulkc2-ufig06.gif" border="0"> = corrected creep rate 
                           </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td"><img align="bottom" src="graphics/bulkc2-ufig07.gif" border="0"> = creep rate at T0 
                           </p>
                        </td>
                     </tr>
                     <tr>
                        <td align="left" colspan="1" rowspan="1" valign="top">
                           <p class="para_td"><img align="bottom" src="graphics/bulkc2-ufig08.gif" border="0"> = correction factor 
                           </p>
                        </td>
                     </tr>
                  </tbody>
               </table><br></li>
            <li><a name="ref65578"></a><p class="para_item">if the creep model parameters <em>K</em><em><sub class="subscript">p</sub></em>, <em>C</em><em><sub class="subscript">p</sub></em>, and <em>C</em><em><sub class="subscript">s</sub></em> are to be specified with FORM = &ldquo;TABLE&rdquo;, then TABLES1 entries (with IDs that appear in TIDXX fields) must be provided in the Bulk Data Section.  In this case, the continuation should not be specified. 
               </p>
            </li>
            <li>
               <p class="para_item">Creep model parameters <em>K</em><em><sub class="subscript">p</sub></em>, <em>C</em><em><sub class="subscript">p</sub></em>, and <em>C</em><em><sub class="subscript">s</sub></em> represent parameters of the uniaxial rheological model as shown in <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref22750');return(false);">Figure 13-</a>. 
               </p>
               <p class="para_item">Tabular values (X<sub class="subscript">i</sub>, Y<sub class="subscript">i</sub>) in the TABLES1 entry correspond to (&sigma;<em><sub class="subscript">i</sub></em>, <em>K<sub class="subscript">pi</sub></em>), (&sigma;<em><sub class="subscript">i</sub></em>, <em>C<sub class="subscript">pi</sub></em>), and (&sigma;<em><sub class="subscript">i</sub></em>, <em>C<sub class="subscript">si</sub></em>)  for the input of <em>K</em><em><sub class="subscript">p</sub></em>, <em>C</em><em><sub class="subscript">p</sub></em>, and <em>C</em><em><sub class="subscript">s</sub></em>, respectively.  For linear viscoelastic materials, parameters <em>K</em><em><sub class="subscript">p</sub></em>, <em>C</em><em><sub class="subscript">p</sub></em>, and <em>C</em><em><sub class="subscript">s</sub></em> are constant and two values of &sigma;<em>i</em> must be specified for the same value of <em>K</em><em><sub class="subscript">p</sub></em><em><sub class="subscript">i</sub></em>, <em>C</em><em><sub class="subscript">p</sub></em><em><sub class="subscript">i</sub></em>, and <em>C</em><em><sub class="subscript">s</sub></em><em><sub class="subscript">i</sub></em>. 
               </p><a name="ref22750"></a><div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-fig21.gif"></p>
               </div>
               <div class="title_figure">Figure. CREEP Parameter Idealization </div>
               <p class="para_item">Creep model parameters, as shown in <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref28376');return(false);">Figure 13-</a> through <a class="links" href="javascript:void(0)" onclick="top.openFile('QRG/14topic_22.html#ref83859');return(false);">Figure 13-</a> below, must have positive values.  If the table look-up results in a negative value, the value will be reset to zero and a warning message (TABLE LOOK-UP RESULTS IN NEGATIVE VALUE OF CREEP MODEL PARAMETER IN ELEMENT ID=****) will be issued. 
               </p><a name="ref28376"></a><div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-fig22.gif"></p>
               </div>
               <div class="title_figure">Figure. K<sub class="subscript">p</sub> Versus &sigma; Example for CREEP 
               </div><a name="ref74055"></a><div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-fig23.gif"></p>
               </div>
               <div class="title_figure">Figure. C<sub class="subscript">p</sub> Versus &sigma; Example for CREEP 
               </div><a name="ref83859"></a><div class="figure">
                  <p align="center"><img align="bottom" src="graphics/bulkc2-fig24.gif"></p>
               </div>
               <div class="title_figure">Figure. C<sub class="subscript">s</sub> Versus &sigma; Example for CREEP 
               </div>
            </li>
            <li><a name="ref35261"></a><p class="para_item">Creep analysis requires an initial static solution at <em>t</em> = <em>0</em>, which can be obtained by specifying a subcase that requests an NLPARM entry with DT = 0.0. 
               </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">MID is restricted to the material identification number of a MAT1 entry. CREEP and MAT1 entries model an elastic-creep material with only elastic strain and creep strain effects. </p>
            </li>
            <li>
               <p class="para_item">Only FORM=CRLAW is allowed. </p>
            </li>
            <li>
               <p class="para_item">T0, EXP, TIDKP, TIDCP, TIDCS, and THRESH are ignored. </p>
            </li>
            <li>
               <p class="para_item">Only TYPE=300 and TYPE=222 are supported. </p>
            </li>
            <li>
               <p class="para_item">NLPARM is not used by SOL 601. Incremental time intervals for SOL 601 creep analysis are determined by the TSTEP entry. </p>
            </li>
         </ol>
      </div>
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