{"id":163874,"date":"2021-11-10T20:07:19","date_gmt":"2021-11-10T20:07:19","guid":{"rendered":"\/forum\/forums\/topic\/ansys-modal-analysis\/"},"modified":"2021-11-15T10:47:37","modified_gmt":"2021-11-15T10:47:37","slug":"ansys-modal-analysis","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ansys-modal-analysis\/","title":{"rendered":"Ansys Modal analysis"},"content":{"rendered":"<div class=\"Item-Body\">\n<div class=\"Message userContent\">\n<p>Hi everyone, i have been working on a space truss model (Mero space truss system) and tried to perform modal analysis. However the first frequency also the whole frequency range from Ansys doesn&#039;t match with my other FE software models (Sofistik and SAP2000): While in sofistik my first frequency is 191.82 Hz and for the first 15 modes it ranges up to 1656 Hz, in Ansys my first frequency is only 155.64 Hz and only ranges up to 302Hz for the first 15 modes.<\/p>\n<p>I tried to cross checked the two models from the material with correct module of elastic, also the cross sections, dimensions, etc, structural self-weight, support reactions, &#8230; All of these are the same however the modal analysis gave me a different results as mentioned. I checked with every single mode and found out that in my Ansys model there is only local modes and when i changed the boundary condition from simply supported to fixed, the frequency range in Ansys doesn&#039;t change too much. This make me think that my beam elements have no sufficient stiffness. I don&#039;t know this assumption is correct or not and I can&#039;t find a way to fix my model.<\/p>\n<p>Can anyone give me some hints where is my problem?<\/p>\n<p>(I can upload my models if needed) <\/p>\n<div class=\"embedExternal embedImage\">\n<div class=\"embedExternal-content\">\n<a class=\"embedImage-link\" href=\"\/forum\/wp-content\/uploads\/forum-uploads\/277\/8QIVB2WEZYYC.png\" rel=\"nofollow noopener\" target=\"_blank\"><br \/>\n<img decoding=\"async\" class=\"embedImage-img\" src=\"\/forum\/wp-content\/uploads\/forum-uploads\/277\/8QIVB2WEZYYC.png\" alt=\"image.png\" \/><br \/>\n<\/a><\/p>\n","protected":false},"template":"","class_list":["post-163874","topic","type-topic","status-closed","hentry","topic-tag-error-modal-frequency"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["1918"],"_bbp_likes_count":["0"],"_bbp_subscription":["239688"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["163874"],"_bbp_forum_id":["27791"],"_bbp_engagement":["58821","197848","239688"],"_bbp_voice_count":["3"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["197334"],"_bbp_last_active_id":["197334"],"_bbp_last_active_time":["2021-11-15 10:47:37"]},"test":"ba-tung-leuni-weimar-de"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/163874","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\/163874\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=163874"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}