{"id":456399,"date":"2026-04-13T17:25:33","date_gmt":"2026-04-13T17:25:33","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ls-dyna-non-uniform-time-sampling-issue\/"},"modified":"2026-04-13T17:25:33","modified_gmt":"2026-04-13T17:25:33","slug":"ls-dyna-non-uniform-time-sampling-issue","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ls-dyna-non-uniform-time-sampling-issue\/","title":{"rendered":"LS-DYNA non-uniform time sampling issue"},"content":{"rendered":"<p>&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;Hi all,&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;TextRun SCXW66434239 BCX8&#8243; lang=&#8221;EN-GB&#8221; xml:lang=&#8221;EN-GB&#8221; data-contrast=&#8221;auto&#8221;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;I&rsquo;m&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;&nbsp;running an&nbsp;&lt;\/span&gt;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;LS-DYNA analysis in Ansys (Explicit Dynamics)&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;&nbsp;with a&nbsp;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;2D plane strain model&lt;\/span&gt;&lt;span class=&#8221;TextRun SCXW66434239 BCX8&#8243; lang=&#8221;EN-GB&#8221; xml:lang=&#8221;EN-GB&#8221; data-contrast=&#8221;auto&#8221;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;, and&nbsp;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;I&rsquo;m&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;&nbsp;having an issue with time sampling of results.&lt;\/span&gt;&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;I defined my output using a constant time interval (&asymp;&nbsp;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;1e-7 s&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;) expecting uniform time steps in the results. However, when I probe results in&nbsp;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;Ansys Mechanical (Velocity Probe &rarr; Tabular Data)&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;, the time values are not exact multiples of 1e-7. For example:&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;0&lt;\/span&gt;&lt;span class=&#8221;LineBreakBlob BlobObject DragDrop SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;SCXW66434239 BCX8&#8243;&gt;&nbsp;&lt;\/span&gt;&lt;br class=&#8221;SCXW66434239 BCX8&#8243;&gt;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;9.77E-08&lt;\/span&gt;&lt;span class=&#8221;LineBreakBlob BlobObject DragDrop SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;SCXW66434239 BCX8&#8243;&gt;&nbsp;&lt;\/span&gt;&lt;br class=&#8221;SCXW66434239 BCX8&#8243;&gt;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;1.95E-07&lt;\/span&gt;&lt;span class=&#8221;LineBreakBlob BlobObject DragDrop SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;SCXW66434239 BCX8&#8243;&gt;&nbsp;&lt;\/span&gt;&lt;br class=&#8221;SCXW66434239 BCX8&#8243;&gt;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;2.93E-07&lt;\/span&gt;&lt;span class=&#8221;LineBreakBlob BlobObject DragDrop SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;SCXW66434239 BCX8&#8243;&gt;&nbsp;&lt;\/span&gt;&lt;br class=&#8221;SCXW66434239 BCX8&#8243;&gt;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;3.91E-07&lt;\/span&gt;&lt;span class=&#8221;LineBreakBlob BlobObject DragDrop SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;SCXW66434239 BCX8&#8243;&gt;&nbsp;&lt;\/span&gt;&lt;br class=&#8221;SCXW66434239 BCX8&#8243;&gt;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;&#8230;&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;So instead of getting exactly 1.00E-07, 2.00E-07, etc., I get slightly shifted values. Because of this, when I try to evaluate results at a specific time, Mechanical returns the&nbsp;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;nearest available value&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;, not the exact time I want.&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;My understanding is that this may be related to LS-DYNA&rsquo;s&nbsp;&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;variable explicit time step&lt;\/span&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;, but I expected the output control to enforce exact time-based sampling.&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;&lt;div class=&#8221;OutlineElement Ltr SCXW66434239 BCX8&#8243;&gt;&lt;p class=&#8221;Paragraph SCXW66434239 BCX8&#8243;&gt;&lt;span class=&#8221;NormalTextRun SCXW66434239 BCX8&#8243;&gt;Is there a way to force truly uniform time output (exact times)?&lt;\/span&gt;&lt;span class=&#8221;EOP SCXW66434239 BCX8&#8243; data-ccp-props=&#8221;{&quot;201341983&quot;:0,&quot;335559739&quot;:0,&quot;335559740&quot;:240}&#8221;&gt;&nbsp;&lt;\/span&gt;&lt;\/p&gt;&lt;\/div&gt;<\/p>\n","protected":false},"template":"","class_list":["post-456399","topic","type-topic","status-publish","hentry","topic-tag-lsdyna"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["456399"],"_bbp_subscription":["675397","13640","480261"],"_bbp_author_ip":["194.80.82.149"],"_bbp_last_reply_id":["456569"],"_bbp_last_active_id":["456569"],"_bbp_last_active_time":["2026-04-16 10:53:26"],"_bbp_reply_count":["6"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["3"],"_bbp_engagement":["675397","13640","480261"],"_btv_view_count":["116"],"_bbp_topic_status":["unanswered"]},"test":"kanteti-vsrulster-ac-uk"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/456399","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/456399\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=456399"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}