{"id":397560,"date":"2024-12-16T07:13:03","date_gmt":"2024-12-16T07:13:03","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-can-we-consider-specific-modes-in-modal-analysis-for-expansion-in-msup-rv\/"},"modified":"2024-12-16T07:53:37","modified_gmt":"2024-12-16T07:53:37","slug":"how-can-we-consider-specific-modes-in-modal-analysis-for-expansion-in-msup-rv","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-can-we-consider-specific-modes-in-modal-analysis-for-expansion-in-msup-rv\/","title":{"rendered":"How can we consider specific modes in modal analysis for expansion in MSUP RV?"},"content":{"rendered":"<p>&lt;p&gt;&lt;p&gt;Hi all,&lt;\/p&gt;&lt;p&gt;I am performing a MSUP Random Vibration (RV) analysis and before solving for the random response, I want to reduce the number of modes used in the analysis. For this, I used the <code>MXPAND<\/code> and <code>MODSELOPTION<\/code> commands during the modal analysis, which works well for reducing the modes in the modal analysis itself. However, when I proceed to the RV analysis, an error occurs stating: &#8216;The mode coefficient values are not on the .mode file. The mode selection cannot be performed.'&lt;\/p&gt;&lt;p&gt;the command snippet which i am using for this is given below,&lt;\/p&gt;&lt;p&gt;! Obtain the Modal Solution&lt;br&gt;\/solu&lt;br&gt;antype, MODAL&lt;br&gt;modopt,LANB,20,,,,,,,,,,! Block Lanczos&lt;br&gt;solve&lt;br&gt;finish&lt;br&gt;! Perform the modal selection and expansion&lt;br&gt;\/solu&lt;br&gt;antype, MODAL, RESTART&lt;br&gt;mxpand,,,, yes,,, MODM ! Mode selection is based on the modal effective mass, and element&lt;br&gt;! results are requested&lt;br&gt;modseloption, .90, no,no, no,no,no ! Only direction X is selected, a minimum of 90% of the total&lt;br&gt;! mass is requested in this direction&lt;br&gt;solve&lt;br&gt;finish&lt;br&gt;! Post-process the modal results or perform a mode superposition analysis&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;&lt;span data-teams=&#8221;true&#8221;&gt;Using this code if i am solving Harmonic it working fine but MSUP RV its not working, is there any extra step i need to add in this code?&lt;\/span&gt;&lt;\/p&gt;&lt;p&gt;&lt;span data-teams=&#8221;true&#8221;&gt;please help&lt;\/span&gt;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-397560","topic","type-topic","status-publish","hentry","topic-tag-Modal_Analysis-1","topic-tag-apdl","topic-tag-error","topic-tag-mode-superposition","topic-tag-random-vibration"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27791"],"_bbp_topic_id":["397560"],"_bbp_subscription":["284329","52629","436953"],"_bbp_author_ip":["203.192.246.174"],"_bbp_last_reply_id":["397761"],"_bbp_last_active_id":["397761"],"_bbp_last_active_time":["2024-12-17 14:37:21"],"_bbp_reply_count":["9"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["3"],"_bbp_engagement":["284329","52629","436953"],"_btv_view_count":["526"],"_bbp_topic_status":["unanswered"],"_edit_last":["52629"],"_bbp_revision_log":["a:1:{i:397570;a:2:{s:6:\"author\";i:52629;s:6:\"reason\";s:0:\"\";}}"]},"test":"balaji-bpcoreel-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/397560","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\/397560\/revisions"}],"predecessor-version":[{"id":397570,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/397560\/revisions\/397570"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=397560"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}