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      <title>Wrinkling Criteria</title>
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      <div class="title_topic4" id="xps10_pagetitle">Wrinkling Criteria</div>
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      <div class="title_division">Description</div>
      <p class="para_division">Predict sheet metal wrinkling during the draw process.</p>
      <div class="title_division">Purpose</div>
      <p class="para_division">The purpose of this check is to ensure that wrinkling does not&nbsp; occur when the sheet metal is locked at the boundary (the holding condition = locked). Wrinkling under this condition indicates that it will be almost impossible to form the part without wrinkling.</p>
      <div class="title_division">Computational Method</div>
      <p class="para_division">The AutoFormTM OneStep solver is used to analyze the formability of the part. The AutoForm OneStep run is a Part Only simulation and preparation of the data for input, launching the simulation, and retrieval of the results is completely automatic.</p>
      <p class="para_division">The results are presented as shown:</p>
      <p class="para_division"><img align="bottom" src="graphics/dfm_wrinkling_examp.gif" border="0"></p>
      <p class="para_division">Analysis of the results of the simulation is done by classifying each element using a Forming Limit Diagram (FLD). For a complete description of the Application of the FLD, see  <a class="links" href="javascript:void(0)" onclick="top.openFile('dieengr/dfm_fld_desc.html');return(false);">FLD Description</a>. Classification of each element as &quot;Failure&quot; (Red), &quot;Caution&quot; (Yellow), and &quot;Safe&quot; (Green) regions is determined from the FLD diagram as shown below:
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      <p class="para_division"><img align="bottom" src="graphics/dfm_wrinkling.gif" border="0"></p>
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