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      <title>TSTEP</title>
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      <div class="title_refTopic" id="xps10_pagetitle">TSTEP </div>
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      <h4 class="refClassification">Transient Time Step Set Selection </h4>
      <p class="para_refTopic">Selects integration and output time steps for linear or nonlinear transient analysis. </p>
      <p class="para_refTopic"><b class="uiTerm">For SOLs 601 and 701: </b> Selects time stepping for advanced nonlinear analysis. 
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      <div class="title_refCategory">Format: </div>
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         <p class="para_refCategory">TSTEP=n </p>
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      <div class="title_refCategory">Examples: </div>
      <div class="refCategoryContent"><pre class="indent">TSTEP=731</pre></div>
      <div class="title_refCategory">Describers:</div>
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                     <p class="para_th"><b class="uiTerm">Describer </b></p>
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                     <p class="para_th"><b class="uiTerm">Meaning </b></p>
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                     <p class="para_td">n </p>
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                     <p class="para_td">Set identification number of a TSTEP or TSTEPNL Bulk Data entry.  (Integer&gt;0) </p>
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                     <p class="para_td">n (For SOLs 601 and 701) </p>
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                     <p class="para_td">Set identification number of a TSTEP Bulk Data entry.  (Integer&gt;0) </p>
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      <div class="title_refCategory">Remarks: </div>
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               <p class="para_item">A TSTEP entry must be selected to execute a linear transient analysis (SOLs 9, 12, 109, or 112) and TSTEPNL for a nonlinear transient analysis (SOLs 129 and 159). </p>
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            <li>
               <p class="para_item">A TSTEPNL entry must be selected in each subcase to execute a nonlinear transient problem. </p>
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            <li>
               <p class="para_item">For the application of time-dependent loads in modal frequency response analysis (SOLs 111 and 146), a TSTEP entry must be selected by the TSTEP command.  The time-dependent loads will be recomputed in frequency domain by a Fourier Transform. </p>
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      <div class="title_refCategory">Remarks related to SOLs 601 and 701: </div>
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               <p class="para_item">In SOL 601, TSTEP selects the solution time steps for a static or transient analysis. </p>
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               <p class="para_item">In SOL 701, the actual time step size may be based on the critical time step size for stability calculated by the program. However, the total solution time is considered. For example, if the TSTEP entry specifies 5 time steps of step size 0.001, the program will execute up to solution time 0.005 using an appropriate time step size. To request that the program use the time step size specified in TSTEP Bulk Data entry, specify XSTEP=1 in the NXSTRAT entry. See the<em> Advanced Nonlinear Theory and Modeling Guide</em>on the critical time step size and when results are output. 
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