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      <title>NXSTRAT</title>
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      <div class="title_refTopic" id="xps10_pagetitle">NXSTRAT </div>
      <hr noshade="true">
      <h4 class="refClassification">Strategy Parameters for SOLs 601 and 701 </h4>
      <p class="para_refTopic">Defines parameters for solution control and strategy in advanced nonlinear structural analysis. </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>
                  </th>
                  <th align="center" colspan="1" rowspan="1">
                     <p class="para_th">5 </p>
                  </th>
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                     <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">NXSTRAT </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">ID </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Param1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Value1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Param2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Value2 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Param3 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Value3 </p>
                  </td>
                  <td align="center" bgcolor="gray" 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">Param4 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Value4 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Param5 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">Value5 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">-etc- </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">Example: </div>
      <div class="refCategoryContent">
         <table border="1" width="100%" align="center">
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            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NXSTRAT </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">AUTO </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">1 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">MAXITE </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">30 </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">RTOL </p>
                  </td>
                  <td align="center" colspan="1" rowspan="1">
                     <p class="para_td">0.005 </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>
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                  <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">ATSNEXT </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">&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>
                  <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">
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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>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Identification number. Currently not used. (Integer &ge; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">PARAMi </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Name of the NXSTRAT parameter. Allowable names are given in Table 8-33. See remark 1 for parameters applicable to SOL 701. (Character) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">VALUEi </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Value of the parameter. See Table 8-33. (Real or integer) </p>
                  </td>
               </tr>
            </tbody>
         </table><br></div>
      <div class="title_refCategory">NXSTRAT Parameters</div>
      <div class="refCategoryContent"><a name="ref33822"></a><div class="title_tableWrapper">Analysis Control</div>
         <table cellpadding="9" width="100%" align="center">
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                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">SOLVER </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the solver to use. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Direct sparse solver </p>
                     <p class="para_td">1 &ndash; Multigrid solver </p>
                     <p class="para_td">2 &ndash; 3D iterative solver. This solver is effective for models with large numbers of higher order 3D solid elements, i.e., CTETRA and CHEXA elements with mid-side nodes.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" height="107" rowspan="1" valign="top">
                     <p class="para_td">AUTO </p>
                  </td>
                  <td align="left" colspan="1" height="107" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether automatic incrementation scheme is enabled. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; No automatic incrementation scheme is used </p>
                     <p class="para_td">1 &ndash; Automatic time stepping (ATS) scheme is enabled </p>
                     <p class="para_td">2 &ndash; Automatic load-displacement control (LDC) scheme is enabled</p>
                     <p class="para_td">3 &ndash; Total load application (TLA) scheme is enabled. Program ignores any time step and time function specified. Instead, 50 time steps of size 0.2 are used with a linear ramp time function (100% load at time of 10.0), and parameters MAXITE=30, ATSSUBD=64, LSEARCH=1 and MAXDISP=0.05*(maximum model dimension) are used.</p>
                     <p class="para_td">4 &ndash; Total load application with stabilization (TLA-S) scheme is enabled. In addition to TLA, stabilization is used, i.e., MSTAB=1, MSFAC=1.0e-10, ATSLOWS=1 and contact damping (determined by the program) are used. </p>
                     <p class="para_td">Note: TLA and TLA-S schemes include the use of the automatic time stepping (ATS) scheme. See sections below for parameters that may be specified for each of these schemes.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NPOSIT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether analysis continues when the system matrix is not positive definite. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Analysis may stop</p>
                     <p class="para_td">1 &ndash; Analysis continues</p>
                     <p class="para_td">Notes:</p>
                     <p class="para_td">If NPOSIT=0, analysis stops unless</p>
                     <ul>
                        <li>
                           <p class="para_item">AUTO &gt; 0 is specified</p>
                        </li>
                        <li>
                           <p class="para_item">contact analysis is being performed.</p>
                        </li>
                     </ul>
                     <p class="para_td">It is not recommended to set NPOSIT=1 for a linear analysis. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MASSTYP </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the type of mass matrix to be used in dynamic analysis. (Integer; Default = 1) </p>
                     <p class="para_td">0 &ndash; Lumped mass is used </p>
                     <p class="para_td">1 &ndash; Consistent mass is used </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822b"></a><div class="title_tableWrapper">Analysis Options</div>
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                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TINT<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Integration order for the local t-direction (through thickness) of shell elements with elasto-plastic materials. By default, 5-point Newton-Cotes is used for single-layered shell and 3-point Newton-Cotes is used for multi-layered shell. Note that 2-point Gauss integration is always used for all shell elements with elastic materials. (Integer; Default = 0). </p>
                     <p class="para_td">1 &le; TINT &le; 6 &ndash; Gauss integration method with integration order TINT </p>
                     <p class="para_td">-3, -5, -7 &ndash; Newton-Cotes integration with order -TINT </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ICMODE<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether incompatible modes are used for 4-node shell elements. (Integer; Default =1 for SOL 601 and 0 for SOL 701) </p>
                     <p class="para_td">0 - Incompatible modes are not used </p>
                     <p class="para_td">1 - Incompatible modes are used </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MSTAB </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether the stiffness matrix stabilization feature is used. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Matrix stabilization is not used </p>
                     <p class="para_td">1 &ndash; Matrix stabilization is used </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MSFAC </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Matrix stabilization factor. (Real; Default = 1.0E-12) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DTDELAY<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Element death time delay. (Real; Default = 0.0) </p>
                     <p class="para_td">When an element is too deformed and becomes &ldquo;dead&rdquo;, its contribution to the overall stiffness of the structure is removed. By specifying DTDELAY &gt; 0.0, the contribution from the element stiffness is gradually reduced to zero over time DTDELAY instead of being suddenly removed. This may help in the convergence of the solution. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">SDOFANG<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Angle used to determine whether a shell mid-surface node is assigned 5 or 6 degrees of freedom. (Real; Default = 5.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DRILLKF<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">On shell grids where the drilling stiffness is zero, this factor is multiplied by the maximum rotational stiffness at the grid and assigned as the drilling stiffness. (0.0 &lt; Real &lt; 1.0; Default = 1.0E-4)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">UPFORM<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether u/p formulation is used for elements. Note that u/p formulation is always used for hyperelastic elements and always not used for hyperfoam elements and elastic elements with Poisson&rsquo;s ratio less than 0.48. It is also not used for gasket elements (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; u/p formulation is not used </p>
                     <p class="para_td">1 &ndash; u/p formulation is used instead of displacement-based formulation </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ULFORM<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates which large strain formulation is used for shell elements. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Updated Lagrangian-Jaumann (ULJ) formulation is used if the old (v4) rigid-target contact algorithm (RTALG=1 in NXSTRAT) is used or SOL 701 is run. Otherwise, Updated Lagrangian-Hencky (ULH) formulation is used. </p>
                     <p class="para_td">1 &ndash; Use ULH formulation </p>
                     <p class="para_td">2 &ndash; Use ULJ formulation </p>
                     <p class="para_td">Note: For 3-D solid, plane strain and axisymmetric elements, ULH formulation is always used for large strains. In restarting from SOL 601 to 701 or vice versa, ULFORM needs to be specified such that both analyses use the same formulation. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DISPOPT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether prescribed displacements are applied to the original configuration or the deformed configuration. This option is only applicable for a restart analysis or when a delay (or arrival) time is specified for the prescribed displacement. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Applied to original configuration </p>
                     <p class="para_td">1 &ndash; Applied to deformed configuration </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LOADOPT<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether prescribed loads (pressure and centrifugal) are deformation-dependent, i.e. the direction and magnitude of the load may change due to large deformation of the structure. This option is only applicable for large displacement analysis, i.e. PARAM,LGDISP,1 (Integer; Default = 1) </p>
                     <p class="para_td">0 &ndash; Load is independent of structural deformation </p>
                     <p class="para_td">1 &ndash; Load is affected by structural deformation </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MAXDISP </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Specifies a limit for the maximum incremental displacement that is allowed for any grid in any equilibrium iteration. This feature is generally useful for contact analysis where rigid body motion exists in a model. A value of 0.0 means there is no limit on displacements. (Real &ge; 0.0; Default = 0.0) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822c"></a><div class="title_tableWrapper">Time Integration</div>
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               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TINTEG </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the time integration method to be used for nonlinear transient analysis. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Use the Newmark method </p>
                     <p class="para_td">1 &ndash; Use the ADINA composite method </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ALPHA </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Alpha coefficient for the Newmark time integration method. (Real; Default = 0.25) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DELTA </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Delta coefficient for the Newmark method. (Real; Default = 0.5) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822d"></a><div class="title_tableWrapper">SOL 701 Time Stepping</div>
         <table cellpadding="9" width="100%" align="center">
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                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XSTEP<sup class="superscript">o</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects time step method used in an explicit time integration analysis. (Integer; Default = 0) </p>
                     <p class="para_td">0 - Time step size is calucated by the program based on the critical time step size. The data in the selected TSTEP bulk data entry is used to calculate the total solution time for the analysis. </p>
                     <p class="para_td">1 - The number of time steps and the time step size as specified in the selected TSTEP bulk data entry is used. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XDTCAL<sup class="superscript">o</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Calculation of the critical time step size may be computationally expensive. This parameter specifies that the critical time step size be re-calculated every XDTCAL time steps. (Integer &gt; 0, Default = 1) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XDTFAC<sup class="superscript">o</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">The critical time step size is calculated based on certain assumptions. It is often necessary, especially for nonlinear analysis, to use a time step size smaller than the calculated critical time step size. The factor multiplied by the calculated critical time step size gives the time step size used in the analysis. (4.0 &gt; Real &gt; 0.0, Default = 0.9) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XMSCALE<sup class="superscript">o</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Specifies the factor to scale the mass (densities) of the entire model (at the beginning of the analysis) to increase the critical time step size required for stability when the explicit time integration scheme is used. See warning in Remark 2. (Real = 1.0, Default = 1.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XDTMIN1<sup class="superscript">o</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">The minimum time step size used to determine if mass scaling will be applied to elements (at the beginning of the analysis) whose critical time step size is smaller than DTMIN1. The amount of mass scaling is calculated for each element so that the critical time step size is equal to DTMIN1. See Remark 2 and warning in Remark 3. (Real = 0.0, Default = 0.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XDTMIN2<sup class="superscript">o</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">The minimum time step size used to determine whether an element will be removed in an explicit time integration analysis. In explicit time integration, the smaller an element size is, the smaller will the critical time step size be. If the critical time step size for an element is smaller than XDTMIN2, the element will be removed in the analysis. See Remark 2 and warning in Remark 3. (Real &gt; 0.0, Default = 0.0) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822e"></a><div class="title_tableWrapper">Iterative Solver</div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ITEMAX </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Maximum number of iterations allowed for the multigrid or 3D-iterative solver to converge. (Integer &gt; 0; Default = 1000 for multigrid solver and 200 for 3D-iterative solver)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EPSIA </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Convergence tolerance EPSIA. (Real; Default = 1.0E-6) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EPSIB </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Convergence tolerance EPSIB. (Real; Default = 1.0E-4) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EPSII </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Convergence tolerance EPSII. (Real; Default = 1.0E-8) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822f"></a><div class="title_tableWrapper">Equilibrium Iteration and Convergence </div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LSEARCH </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Flag to indicate the use of line searches within the iteration scheme. (Integer; Default = 0)</p>
                     <p class="para_td">0&ndash; Line search is not used</p>
                     <p class="para_td">1 &ndash; Line search is used </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LSLOWER </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Lower bound for line search. (0.0 &le; Real &lt; 1.0; Default = 0.001) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LSUPPER </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Upper bound for line search. (1.0 &le; Real; Default = 1.0 for contact analysis and 8.0 for analysis with no contact)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">PLASALG</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the algorithm used in plasticity. (Integer; Default = 1) </p>
                     <p class="para_td">1 &ndash; Algorithm 1 is used</p>
                     <p class="para_td">2 &ndash; Algorithm 2 is used</p>
                     <p class="para_td">Note: For a given time step size, if the iterations do not converge with algorithm 1 because the Jacobian determinant in the elements becomes non-positive, switching to algorithm 2 can sometimes enable convergence.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MAXITE </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Maximum number of iterations within a time step. If the maximum number of iterations is reached without achieving convergence (see CONVCRI parameter), the program will stop unless the automatic time stepping (ATS) or load displacement control scheme is selected (see parameter AUTO). (1 &le; Integer &le; 999; Default = 15) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CONVCRI </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Convergence Criteria. (Integer; Default = 0)0 &ndash; Convergence based on energy1 &ndash; Convergence based on energy and force2 &ndash; Convergence based on energy and displacement3 &ndash; Convergence based on force4 &ndash; Convergence based on displacement </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ETOL </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Relative energy tolerance. (Real; Default = 0.001 if AUTO&ne;2; Default = 1.0e-6 if AUTO=2)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RTOL </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Relative force (and moment) tolerance (Real; Default = 0.01) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RNORM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Reference force. (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RMNORM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Reference moment. (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RCTOL </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Relative contact force tolerance. (Real; Default = 0.05) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DTOL </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Relative displacement (translation and rotation) tolerance. (Real; Default = 0.01) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DNORM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Reference translation. (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">DMNORM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Reference rotation. (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">STOL </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Line search convergence tolerance. (Real; Default = 0.5) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RCONSM </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Reference contact force. (Real; Default = 0.01) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ENLSTH </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Line search energy threshold. (Real; Default = 0.0) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822g"></a><div class="title_tableWrapper">Automatic Time Stepping (ATS) Scheme </div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ATSSUBD </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Number that limits the smallest time step size when the automatic time stepping (ATS) scheme is used. For a time step size of DT, the program will stop if convergence is not achieved and the next subdivided time step size is less than DT/ATSSUBD. (Integer &ge; 1; Default = 10) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ATSMXDT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Factor that limits the maximum time step size when the automatic time stepping (ATS) scheme is used. The ATS scheme may increase the time step size after convergence is achieved. However, for a time step size of DT, the program will not use a time step size greater than ATSMXDT * DT. (Real; Default = 3.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ATSNEXT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Flag controls what time step size to use once convergence is reached after an ATS subdivision. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Automatically set by program. For contact analysis, ATSNEXT = 2, otherwise ATSNEXT = 1. </p>
                     <p class="para_td">1 &ndash; Use the time step size that gave convergence, i.e., the reduced time step that led to convergence is used again. </p>
                     <p class="para_td">2 &ndash; Return to the original time step size, i.e., the original time step size before any subdivision took place is used. </p>
                     <p class="para_td">3 &ndash; Use a time step size such that the solution time matches the original solution time specified by the user. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ATSDFAC </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Division factor used calculate the sub-increment time step size. If current time step size is DT and convergence is not achieved, the next time step size will be DT/ATSDFAC. (Real &gt; 1.0; Default = 2.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ATSLOWS </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Flag whether a low-speed dynamics analysis is performed instead of a static analysis. (Integer; Default = 0)0 &ndash; Low-speed dynamics option is not activated 1 &ndash; Low-speed dynamics is performed </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ATSDAMP </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Damping factor used in low-speed dynamics analysis. (Real &ge; 0.0; Default = 1.0e-4) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822h"></a><div class="title_tableWrapper">Load Displacement Control (LDC) Scheme </div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCGRID </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Grid point id at which a displacement is prescribed for the first solution step. (Integer &gt; 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCDOF </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Degree of freedom for prescribed displacement at grid point LDCGRID. (1&le; Integer &le; 6) </p>
                     <p class="para_td">1 &ndash; X translation </p>
                     <p class="para_td">2 &ndash; Y translation </p>
                     <p class="para_td">3 &ndash; Z translation </p>
                     <p class="para_td">4 &ndash; X rotation </p>
                     <p class="para_td">5 &ndash; Y rotation </p>
                     <p class="para_td">6 &ndash; Z rotation </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCDISP </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Prescribed displacement at grid point LDCGRID for the first solution step. (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCIMAX </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Displacement convergence factor used to limit the maximum incremental displacement during a solution step. (Real; Default = 3.0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCDMAX </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Maximum (absolute magnitude) displacement (for the degree of freedom specified by LDCDOF) at the grid point LDCGRID allowed during the analysis. When the displacement reaches or exceeds LDCDMAX, the program will stop the analysis. See Section 6.2.4 in Advanced Nonlinear Theory and Modeling Guide for other criteria that determines when an LDC solution will stop. (Real) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCCONT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Flag whether the solution is terminated when the first critical point on the equilibrium path is reached. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Solution stops </p>
                     <p class="para_td">1 &ndash; Solution continues </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">LDCSUBD </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Maximum number of arc length subdivisions allowed. (Integer &ge; 1; Default = 10) </p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822i"></a><div class="title_tableWrapper">Total Load Application (TLA) Scheme</div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLANSTP</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Number of time steps to use for the solution. The step size is automatically adjusted to obtain a total time of 10.0. (Integer &gt; 0; Default = 50)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLAMXIT</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Maximum number of equilibrium iterations allowed to achieve convergence in any time step (subdivided or accelerated). (1 &le; Integer &le; 999; Default = 30)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLAMXDF</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Maximum displacement factor. The maximum incremental displacement allowed in any time step is equal to TLAMXDF * (maximum model dimension). TLAMXDF = 0.0 means there is no limit on the maximum incremental displacement. (Real &ge; 0.0; Default = 0.05)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLASTBF</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Stiffness matrix stabilization factor. If TLASTBF = 0.0, then the stiffness matrix stabilization feature is not used. Applicable only to TLA-S (AUTO=4) scheme. (Real &ge; 0.0; Default = 1.0E-10)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLALSDF</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Low-speed dynamics damping factor. If TLALSDF = 0.0, then the low-speed dynamics option is not used. Applicable only to TLA-S (AUTO=4) scheme. (Real &ge; 0.0; Default = 1.0E-4)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLALSMF</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Low-speed dynamics inertia factor. Applicable only to TLA-S (AUTO=4) scheme. (0.0 &le; Real  &le; 1.0; Default = 1.0)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TLACTDF</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Contact damping factor. The amount of contact damping used in the solution is equal to TLACTDF * (damping determined by the program). If TLACTDF = 0.0, then contact damping is not used. Applicable only to TLA-S (AUTO=4) scheme. (Real &ge; 0.0; Default = 0.001)</p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822j"></a><div class="title_tableWrapper">Contact Control</div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">IMPACT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Impact control scheme (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; No special treatment is applied for impact problems </p>
                     <p class="para_td">1 &ndash; Post impact adjustment of velocities and accelerations is applied </p>
                     <p class="para_td">2 &ndash; Modified parameters are used in Newmark time integration scheme </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NSUPP </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Number of iterations for pairing contactor node to target segment. If NSUPP &gt; 0, during the first NSUPP iterations, the pairing target segment is recorded for each contactor node. From iteration NSUPP+1, if a target segment in the recorded list is repeated, it is &ldquo;frozen&rdquo; to be the pairing target segment for the remaining equilibrium iterations in that time step. Specifying NSUPP &gt; 0 may help in the convergence for certain problems. (0 &le; Integer &le; 99; Default = 0) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RTSUBD </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the subdivision scheme used in the old (RTALG=1) implicit rigid-target contact algorithm when the tensile contact force is too large. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Subdivision is based on the magnitude of the tensile contact force, i.e., the larger the magnitude, the smaller will be the subdivided time step size. </p>
                     <p class="para_td">1 &ndash; Subdivision is based on the global automatic time stepping (ATS) subdivsion settings. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CSTYPE<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the type of contact segment to use. (Integer; Default = 1)</p>
                     <p class="para_td"> 0 &ndash; Use linear contact segment </p>
                     <p class="para_td">1 &ndash; Use element-based contact segment which gives better contact traction results</p>
                     <p class="para_td">Note: CSTYPE = 1 is only applicable for contact algorithm TYPE = 0 or XTYPE = 0 or 1 in BCTPARA entry.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CTDISP</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the default displacement formulation used for contact analysis. A different formulation may be selected for each individual contact set via BCTPARA entry. (Integer; Default = 0 / 2) </p>
                     <p class="para_td">0 or 2 &ndash; Use large displacement formulation (contact conditions are updated) (default)</p>
                     <p class="para_td">1 &ndash; Use small displacement formulation (contact conditions are not updated)</p>
                     <p class="para_td">CTDISP is a global option since it applies to all contact definitions in the model. If you would like to prevent/allow a specific contact set from updating, the DISP option on the BCTPARA bulk entry can be used.</p>
                     <p class="para_td">Note: If CTDISP = 1 is selected, the search of target segments for the contactor nodes is performed only at the beginning of the analysis.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RTALG<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the rigid-target algorithm to use. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Use the current algorithm </p>
                     <p class="para_td">1 &ndash; Use the old (v4) algorithm</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">FRICALG</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Selects the friction algorithm to use. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Use the current algorithm </p>
                     <p class="para_td">1 &ndash; Use the old (v4) algorithm</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CTDAMP</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether stabilization damping is applied and how it is applied for contact analysis. This feature is generally useful when rigid body motion exists in a model. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; No stabilization damping is applied </p>
                     <p class="para_td">1 &ndash; Stabilization damping is applied at the first time step only. The specified damping coefficients are applied and ramped down to zero by the end of the first time step. </p>
                     <p class="para_td">2 &ndash; The specified stabilization damping coefficients are applied at all time steps.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CTDAMPN</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Specifies the normal stabilization damping coefficient. (Real &ge; 0.0, Default = 0.0)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CTDAMPT</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Specifies the tangential stabilization damping coefficient. (Real &ge; 0.0, Default = 0.0)</p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822k"></a><div class="title_tableWrapper">Restart Options </div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">MODEX<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates the mode of execution. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Normal analysis run, i.e. not a restart analysis </p>
                     <p class="para_td">1 &ndash; Restart analysis </p>
                     <p class="para_td">The restart (.res) file from a previous run must exist to do a restart analysis. The filename and location of the restart file is determined by the &ldquo;dbs&rdquo; keyword. By default, dbs points to the current working directory with the prefix of the current job name. Note that keyword scratch=no must be used when running a restart analysis.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">TSTART<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Solution starting time. If MODEX=1, TSTART must equal a solution time in which data was saved in a previous run. If TSTART = 0.0, the last time step in the restart file is used. (Real, Default = 0.0)</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">IRINT<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Frequency of saving the analysis results in the restart file. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; IRINT is set to 1 when implicit time integration is used and set to the number of steps in the first time step block when explicit time integration is used. </p>
                     <p class="para_td">&gt; 0 &ndash; Restart file is overwritten every IRINT time steps</p>
                     <p class="para_td">&lt; 0 &ndash; Restart file is appended every IRINT time steps</p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822l"></a><div class="title_tableWrapper">Other Parameters</div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">NSUBGRP<sup class="superscript">*</sup></p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Number of sub-groups to divide large number of elements with same property ID into. Normally, elements with same type and property ID are placed into a group. If a group contains more than 1000 elements and NSUBGRP &gt; 1, the elements are placed into NSUBGRP sub-groups for more efficient processing. (Integer &gt; 0; Default = 1) </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">XTCURVE<sup class="superscript">*</sup> 
                     </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether the table in TABLES1 entry is extended by linear extrapolation of the two last points. (Integer; Default = 1) </p>
                     <p class="para_td">0 &ndash; Table is not extended. This option may be used to allow element rupture at the last specified strain value. </p>
                     <p class="para_td">1 &ndash; Table is extended  </p>
                     <p class="para_td">Note: XTCURVE is only applicable for the multilinear-plastic material model.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">CVSSVAL<sup class="superscript">*</sup> 
                     </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates whether the values in TABLES1 entry are converted from engineering stress-strain to true stress-strain. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; No conversion of stress strain value </p>
                     <p class="para_td">1 &ndash; Convert engineering stress and strain values to true stress and strain values. </p>
                     <p class="para_td">Note: CVSSVAL is only applicable for the multilinear-plastic material model.</p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ELRESCS<sup class="superscript">*</sup> 
                     </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates the coordinate system used for output of nonlinear 3D element stress/strain results. For linear results, the coordinate system used for output is specified by CORDM in PSOLID entry. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; Results are output in element coordinate system </p>
                     <p class="para_td">1 &ndash; Results are output material coordinate system </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">BOLTSTP</p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Number of steps for applying the bolt pre-load force. BOLTSTP may be used to apply the bolt pre-load force incrementally if the solution fails to converge when the total pre-load force is applied in one step. (Integer &gt; 0; Default = 1)</p>
                  </td>
               </tr>
            </tbody>
         </table><br><a name="ref33822m"></a><div class="title_tableWrapper">Translation Options </div>
         <table cellpadding="9" width="100%" align="center">
            <colgroup span="1">
               <col span="1" width="18.72*">
               <col span="1" width="81.28*">
            </colgroup>
            <thead>
               <tr>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Name </p>
                  </th>
                  <th align="left" colspan="1" rowspan="1">
                     <p class="para_th">Description  </p>
                  </th>
               </tr>
            </thead>
            <tbody>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">ELCV </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Convert 8-node to 9-node quadrilateral (plane strain, axisymmetric and shell) elements and 20-node to 27-node brick elements. Note that this also converts 6-node to 7-node triangular (plane strain and axisymmetric) elements and 10-node to 11-node tetrahedral elements. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; No conversion of elements </p>
                     <p class="para_td">1 &ndash; Convert elements as described above; nodal coincidence is not checked against existing nodes and new generated nodes are always created. </p>
                     <p class="para_td">2 &ndash; Convert elements as described above; nodal coincidence is checked against existing nodes and a new node will not be created at a location if a node already exist at that location. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EQRBAR </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates how RBAR elements are handled. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; RBAR is simulated using rigid option in small displacement analysis and using flexible option in large displacement analysis. </p>
                     <p class="para_td">1 &ndash; RBAR is simulated using rigid option (i.e. simulated by rigid link or constraint equations as determined by program) </p>
                     <p class="para_td">2 &ndash; RBAR is simulated using flexible option (i.e. simulated by spring or beam elements as determined by program) </p>
                     <p class="para_td">3 &ndash; RBAR is simulated by spring elements </p>
                     <p class="para_td">See Section 2.7 of Advanced Nonlinear Theory and Modeling Guide for details on how RBAR elements are handled. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">EQRBE2 </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Indicates how RBE2 elements are handled. (Integer; Default = 0) </p>
                     <p class="para_td">0 &ndash; RBE2 is simulated using rigid option in small displacement analysis and using flexible option in large displacement analysis. </p>
                     <p class="para_td">1 &ndash; RBE2 is simulated using rigid option (i.e. simulated by rigid links or constraint equations as determined by program) </p>
                     <p class="para_td">2 &ndash; RBE2 is simulated using flexible option (i.e. simulated by spring or beam elements as determined by program) </p>
                     <p class="para_td">3 &ndash; RBE2 is simulated by spring elements </p>
                     <p class="para_td">See Section 2.7 of Advanced Nonlinear Theory and Modeling Guide for details on how RBE2 elements are handled. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">SPRINGK </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Stiffness of spring elements that simulate RBAR or RBE2 elements. (Real, Default = 0.0) </p>
                     <p class="para_td">If SPRINGK = 0.0, program automatically sets SPRINGK according to the following calculations. </p>
                     <p class="para_td">SPRINGK = EMAX * LMODEL </p>
                     <p class="para_td">where EMAX = maximum Young&rsquo;s Modulus of materials in the model and LMODEL = largest dimension of the model. If no material is specified in the model, EMAX is set to 1.0E12. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">BEAME </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Young&rsquo;s Modulus of material assigned to beam elements that simulate RBAR or RBE2 elements. (Real, Default = 0.0) </p>
                     <p class="para_td">If BEAME = 0.0, BEAME is set to EMAX * 100.0 where EMAX = maximum Young&rsquo;s Modulus of materials in the model. If no material is specified in the model, EMAX is set to 1.0E12. </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">BEAMA </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Circular cross section area of beam elements that simulate RBAR or RBE2 elements. (Real, Default = 0.0) </p>
                     <p class="para_td">If BEAMA = 0.0, program automatically sets BEAMA according to the following calculation: </p>
                     <p class="para_td">BEAMA = (LMODEL * .01)<sup class="superscript">2</sup> where LMODEL = largest dimension of the model 
                     </p>
                  </td>
               </tr>
               <tr>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">RBLCRIT </p>
                  </td>
                  <td align="left" colspan="1" rowspan="1" valign="top">
                     <p class="para_td">Critical length for determining how RBAR and RBE2 elements are simulated when the rigid or flexible option is used to simulate RBAR (see EQRBAR) and RBE2 (see EQRBE2). (Real, Default = 0.0) </p>
                     <p class="para_td">If RBLCRIT = 0.0, then </p>
                     <p class="para_td">if EQRBAR (or EQRBE2) = 1, </p>
                     <p class="para_td">RBLCRIT = LMODEL * 1.0E-6 </p>
                     <p class="para_td">if EQRBAR (or EQRBE2) = 2, </p>
                     <p class="para_td">RBLCRIT = LMODEL * 1.0E-3 </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">Parameters applicable to SOL 701 are: </p>
               <ul>
                  <li>
                     <p class="para_item">XSTEP, XDTCAL, XDTFAC, XMSCALE, XDTMIN1 and XDTMIN2 are only used for SOL 701. These parameters are indicated in the table with a superscript &lsquo;<sup class="superscript">o</sup>&rsquo;. 
                     </p>
                  </li>
                  <li>
                     <p class="para_item">TINT, ICMODE, DTDELAY, SDOFANG, UPFORM, ULFORM, LOADOPT, MODEX, TSTART, IRINT, NSUBGRP, ELRESCS, XTCURVE and CVSSVAL parameters can be used for SOL 701. These parameters are indicated in the table with a superscript<sup class="superscript">&lsquo;*&rsquo;</sup>. 
                     </p>
                  </li>
               </ul>
            </li>
            <li>
               <p class="para_item">XMSCALE, XDTMIN1 and XDTMIN2 may be used together. XDTMIN1 and DTMIN2 are applied after XMSCALE is applied. If XDTMIN1 and XDTMIN2 are both used, XDTMIN1 should be greater than XDTMIN2. If XDTMIN2 = XDTMIN1 is specified, XDTMIN1 will be ignored. </p>
            </li>
            <li>
               <p class="para_item">WARNING: Specifying XMSCALE &gt; 1.0, XDTMIN1 &gt; 0.0 or XDTMIN2 &gt; 0.0 may change the model significantly. Hence, extra care should be exercised in examining the results when any of these parameters are used. </p>
            </li>
         </ol>
      </div>
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