{"id":355833,"date":"2024-03-07T08:20:02","date_gmt":"2024-03-07T08:20:02","guid":{"rendered":"\/forum\/forums\/topic\/rigid-body-from-a-mass21-element-connected-by-rbe3\/"},"modified":"2024-03-07T08:20:02","modified_gmt":"2024-03-07T08:20:02","slug":"rigid-body-from-a-mass21-element-connected-by-rbe3","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rigid-body-from-a-mass21-element-connected-by-rbe3\/","title":{"rendered":"Rigid body from a MASS21 element connected by RBE3"},"content":{"rendered":"<p>Hi,<\/p>\n<p>I&#8217;m doing a modal analysis using the perturbation method. In this modal analysis I represent a part of my model using a MASS21 element with KEYOPT(3)=0, meaning I have rotary inertia.<\/p>\n<p>This MASS21 element is connected to many nodes from SOLID187 elements using RBE3, some with Ux and Uy degrees of freedom, others with Ux, Uy and Uz. Thoses nodes are not colinears<\/p>\n<p>When done with the MASS21 element, the modal analysis returns 3 rigid body modes with high mass participation in the rotation degree of freedoms. I understand the the slaves can return rotational moment according to the element referene guide, but I feel like the mass21 element can still freely rotate. Without the MASS21 element those rigid body modes don&#8217;t appear.<\/p>\n<p>I dont understand how can I link the consequences of the rotation of that mass element to be seen as translation for the SOLID187 element, using the distance between the slave node and the MASS21 node, in order to remove those 3 rigid body modes.<\/p>\n<p>Thanks in advance for your help.<\/p>\n<p>Seb<\/p>\n","protected":false},"template":"","class_list":["post-355833","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["58345","20905"],"_bbp_author_ip":["23.52.43.10"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1491"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["355833"],"_bbp_forum_id":["27791"],"_bbp_engagement":["20905","58345"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["356137"],"_bbp_last_active_id":["356137"],"_bbp_last_active_time":["2024-03-08 17:03:19"]},"test":"sebastien-arrivetjimmy-energy-eu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/355833","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\/355833\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=355833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}