{"id":365044,"date":"2024-05-01T11:07:13","date_gmt":"2024-05-01T11:07:13","guid":{"rendered":"\/forum\/forums\/topic\/how-can-solve-xkf-in-matlab-using-stiffness-matrix-from-apdl\/"},"modified":"2024-05-05T06:16:02","modified_gmt":"2024-05-05T06:16:02","slug":"how-can-solve-xkf-in-matlab-using-stiffness-matrix-from-apdl","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-can-solve-xkf-in-matlab-using-stiffness-matrix-from-apdl\/","title":{"rendered":"How can solve x=K\\F in MATLAB using stiffness matrix from APDL?"},"content":{"rendered":"<p>I have exported a stiffness matrix from modal analysis using the SMAT command and then carried out a static analysis by applying a load on a specific node. Knowing the node where the force was applied and having the symmetric stiffness matrix, I attempted a simple static analysis in MATLAB using <code>X=K\\F<\/code> to calculate displacement. However, the values turned out to be very small across the board.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/04-05-2024-1714817833-mceclip0.png\" width=\"916\" height=\"502\"><\/p>\n<p>&nbsp;<\/p>\n<p>I addressed the issue of the difference in node IDs between the stiffness matrix and those displayed in Workbench by using MapForward vectors and NOD2BCS to ensure the load is applied to the correct node. Despite this, the results are still discrepant.&nbsp;<\/p>\n<p><a class=\"wp-colorbox-image cboxElement\" href=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/01-05-2024-1714558435-mceclip0.png\"><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/05\/01-05-2024-1714558435-mceclip0.png\" width=\"291\" height=\"253\"><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>I would be grateful if you could let me know where I might have gone wrong!<\/p>\n","protected":false},"template":"","class_list":["post-365044","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["80516","88"],"_bbp_author_ip":["23.196.2.137"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["323"],"_bbp_topic_status":["unanswered"],"_edit_lock":["1714889699:294145"],"_bbp_topic_id":["365044"],"_bbp_forum_id":["27791"],"_bbp_engagement":["88","80516"],"_bbp_voice_count":["2"],"_bbp_reply_count":["2"],"_bbp_last_reply_id":["365509"],"_bbp_last_active_id":["365509"],"_bbp_last_active_time":["2024-05-04 08:35:55"]},"test":"dhjang4522gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/365044","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":1,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/365044\/revisions"}],"predecessor-version":[{"id":365556,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/365044\/revisions\/365556"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=365044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}