{"id":43317,"date":"2020-04-27T18:04:03","date_gmt":"2020-04-27T18:04:03","guid":{"rendered":"\/forum\/forums\/topic\/modal-analysis-eigenvector-reversal\/"},"modified":"2020-04-27T18:04:03","modified_gmt":"2020-04-27T18:04:03","slug":"modal-analysis-eigenvector-reversal","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/modal-analysis-eigenvector-reversal\/","title":{"rendered":"Modal Analysis &#8211; Eigenvector Reversal"},"content":{"rendered":"<p>When performing modal analysis, the mode shapes and their corresponding frequencies are the eigenvectors and eigenvalues obtained when solving the governing equations. I am solving similar designs in Mechanical APDL, where everything is exactly the same except for slight differences in the design geometry and the meshes, yet the mode shapes are sometimes being returned in reverse (i.e. they are backwards) when compared to the other solutions. I can easily fix them by multiplying the eigenvector and eigenvalue by -1, but ideally the eigenvectors would always be in the same direction. Is there a way to fix this?<\/p>\n","protected":false},"template":"","class_list":["post-43317","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["15498"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["762"],"_bbp_subscription":["250549"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["43317"],"_bbp_forum_id":["27791"],"_bbp_engagement":["200","176385","185156"],"_bbp_voice_count":["3"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["139022"],"_bbp_last_active_id":["139022"],"_bbp_last_active_time":["2021-01-16 23:49:57"]},"test":"gb17"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/43317","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\/43317\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=43317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}