{"id":395917,"date":"2024-12-02T09:03:30","date_gmt":"2024-12-02T09:03:30","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/cross-coupled-stiffness-elements-in-ls-dyna\/"},"modified":"2024-12-02T09:03:30","modified_gmt":"2024-12-02T09:03:30","slug":"cross-coupled-stiffness-elements-in-ls-dyna","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/cross-coupled-stiffness-elements-in-ls-dyna\/","title":{"rendered":"Cross-coupled stiffness elements in LS-DYNA"},"content":{"rendered":"<p>&lt;p&gt;Hello!&lt;br&gt;&lt;br&gt;I am interested in modelling e.g. simple journal bearings represented by two-dimensional spring elements in rotor dynamic simulations.&nbsp;&lt;br&gt;&lt;br&gt;The bearing stiffness matrix (and damping matrix) is generally on the form<strong> [K] <\/strong>= [k_xx k_xy; k_yx k_yy]. The bearing is thus two dimensional and only gives a force output in a plane defined by the x and y coordinates.&lt;br&gt;&lt;br&gt;I am familiar with the one-dimensional spring elements (e.g. *ELEMENT_DISCRETE AND and MAT_ELASTIC_SPRING_DISCRETE_BEAM) and they do the job perfectly for the diagonal stiffnesses. However, I am not sure how to incorporate the cross-coupling entries in a simple way.&lt;br&gt;&lt;br&gt;*ELEMENT_DIRECT_MATRIX_INPUT seems like a reasonable option, but it seems to require some work with the DMIG-files &#8211; which would be a last resort option. If you have any good tutorials for this, please let me know :-)&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-395917","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["395917"],"_bbp_subscription":["487963","13694"],"_bbp_author_ip":["130.240.77.45"],"_bbp_reply_count":["10"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["487963","13694"],"_btv_view_count":["899"],"_bbp_topic_status":["unanswered"],"_bbp_last_reply_id":["397894"],"_bbp_last_active_id":["397894"],"_bbp_last_active_time":["2024-12-18 17:31:41"]},"test":"simon-paajarviltu-se"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/395917","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\/395917\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=395917"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}