{"id":458206,"date":"2026-05-15T06:22:24","date_gmt":"2026-05-15T06:22:24","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-do-a-shock-vibration-with-lsdyna-explicit\/"},"modified":"2026-05-15T06:22:24","modified_gmt":"2026-05-15T06:22:24","slug":"how-to-do-a-shock-vibration-with-lsdyna-explicit","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-do-a-shock-vibration-with-lsdyna-explicit\/","title":{"rendered":"How to do a shock vibration with Lsdyna explicit"},"content":{"rendered":"<p>&lt;p&gt;Hello gentlemen\uff0c&lt;\/p&gt;&lt;p&gt;I want to do a shock vibration with lsdyna explicit,&nbsp;shock condition: 18G, 6ms, half sine wave,Y direction&lt;\/p&gt;&lt;p&gt;Question 1: I use the keyword *BOUNDARY_PRESCRIBED_MOTION_RIGID to apply the acceleration, but I found I have to release the freedom of Y on the base fix points so that the acceleration can be normal (18G). Unlike the random vibration and response spectrum analysis, I can fully fixed the base and apply the acceleration at the same time. Can you help me to explain it?&lt;\/p&gt;&lt;p&gt;Question 2: When I was apply the acceleration, Do I need to apply a initial velocity on the oppsite direction of the acceleration? This question really confused me. I did not find a similar example from the dynaexample.&lt;\/p&gt;&lt;p&gt;If any one have a K file model with similar condition, It will be really thanksful to share with me. Thank you!&lt;\/p&gt;&lt;div&gt;&nbsp;&lt;\/div&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-458206","topic","type-topic","status-publish","hentry","topic-tag-LS-DynaSolverExplicitDynamics-1","topic-tag-shock-analsysis-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["458206"],"_bbp_subscription":["687802","58821"],"_bbp_author_ip":["27.115.36.90"],"_bbp_last_reply_id":["458246"],"_bbp_last_active_id":["458246"],"_bbp_last_active_time":["2026-05-15 11:31:40"],"_bbp_reply_count":["3"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["687802","58821"],"_btv_view_count":["84"],"_bbp_topic_status":["unanswered"]},"test":"bo-zhoucelestica-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/458206","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\/458206\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=458206"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}