{"id":387743,"date":"2024-10-01T22:47:37","date_gmt":"2024-10-01T22:47:37","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-hourglass-energy\/"},"modified":"2024-10-01T22:47:37","modified_gmt":"2024-10-01T22:47:37","slug":"negative-hourglass-energy","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-hourglass-energy\/","title":{"rendered":"Negative Hourglass energy"},"content":{"rendered":"<p>&lt;p&gt;Hi,&nbsp;&lt;\/p&gt;&lt;p&gt;I am currently running vehicle collision simulations with guardrails using LS-DYNA. However, I noticed that the hourglass energy in my model becomes negative midway through the simulation, as shown in the attached figure. I have tried adjusting the hourglass control coefficients and switched from Type 4 to Type 5, but the issue still persists.&lt;\/p&gt;&lt;p&gt;Could you please advise on how to resolve this problem? Any suggestions or recommended settings for managing hourglass energy in such cases would be greatly appreciated.&lt;\/p&gt;&lt;p&gt;Thank you in advance for your assistance.&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;Best,&lt;\/p&gt;&lt;p&gt;Fatemeh&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/01-10-2024-1727822712-mceclip0.png\" \/>&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-387743","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["338821","37202","466782"],"_bbp_author_ip":["128.250.0.47"],"_btv_view_count":["535"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["387743"],"_bbp_forum_id":["27814"],"_bbp_engagement":["37202","338821","466782"],"_bbp_voice_count":["3"],"_bbp_reply_count":["2"],"_bbp_last_reply_id":["388468"],"_bbp_last_active_id":["388468"],"_bbp_last_active_time":["2024-10-08 02:01:44"]},"test":"fatemesafariengyahoo-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/387743","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\/387743\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=387743"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}