{"id":395618,"date":"2024-11-28T07:50:04","date_gmt":"2024-11-28T07:50:04","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/transient-analysis-displacement-profile\/"},"modified":"2024-11-28T07:50:04","modified_gmt":"2024-11-28T07:50:04","slug":"transient-analysis-displacement-profile","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/transient-analysis-displacement-profile\/","title":{"rendered":"Transient Analysis &#8211; Displacement Profile"},"content":{"rendered":"<p>&lt;p&gt;Hello,&lt;\/p&gt;&lt;p&gt;I am trying to perform a transient analysis using a modal analysis approach.&lt;\/p&gt;&lt;p&gt;The problem involves imposing a displacement profile to excite the base of a stair structure.&lt;\/p&gt;&lt;p&gt;When checking the displacement profile at the base, it matches the input profile exactly. However, when I compare the velocity and acceleration profiles obtained at the base, they differ significantly from the ones that should analytically result from differentiating the displacement profile with respect to time.&lt;\/p&gt;&lt;p&gt;On the other handa, when applying an acceleration profile instead of a displacement profile, all the acceleration, velocity and displacement profiles at the excited base match closely with the analytically calculated ones.&lt;\/p&gt;&lt;p&gt;This occurs while using the same number of steps and time steps for both analyses:&lt;\/p&gt;&lt;p&gt;Number of Steps: 3400 (each one 0.5ms)&lt;\/p&gt;&lt;p&gt;Time step: 0.25 ms&lt;\/p&gt;&lt;p&gt;This provides many integration points for better accuracy.&lt;\/p&gt;&lt;p&gt;Could someone explain the reason behind this behaviour? The stresses obtained applying displacement or acceleration profiles are quite similar.&lt;\/p&gt;&lt;p&gt;Thank you in advance.&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-395618","topic","type-topic","status-publish","hentry","topic-tag-modeextraction-1","topic-tag-Modal_Analysis-1","topic-tag-2d","topic-tag-acceleration-1","topic-tag-modal","topic-tag-static-structural","topic-tag-transient","topic-tag-transient-structural"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27791"],"_bbp_topic_id":["395618"],"_bbp_subscription":["454280","58821"],"_bbp_author_ip":["136.226.214.83"],"_bbp_reply_count":["2"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["454280","58821"],"_btv_view_count":["277"],"_bbp_topic_status":["unanswered"],"_bbp_last_reply_id":["395633"],"_bbp_last_active_id":["395633"],"_bbp_last_active_time":["2024-11-28 10:09:54"]},"test":"chema-pinero-vilelagmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/395618","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\/395618\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=395618"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}