{"id":167207,"date":"2023-04-05T14:33:09","date_gmt":"2023-04-05T14:33:09","guid":{"rendered":"\/knowledge\/forums\/topic\/why-dont-ansys-harmonic-results-match-abaqus-for-a-6-damping-value-if-we-use-dmprat-03-the-results-match\/"},"modified":"2023-07-31T12:32:31","modified_gmt":"2023-07-31T12:32:31","slug":"why-dont-ansys-harmonic-results-match-abaqus-for-a-6-damping-value-if-we-use-dmprat-03-the-results-match","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/why-dont-ansys-harmonic-results-match-abaqus-for-a-6-damping-value-if-we-use-dmprat-03-the-results-match\/","title":{"rendered":"Why don&#8217;t ANSYS harmonic results match ABAQUS for a 6% damping value?  If we use dmprat,.03 the results match."},"content":{"rendered":"<p>Many codes use &#8220;Loss Tangent&#8221; to define damping.  In Chapter 1 of the WB Mechanical Dynamics Training notes there is table of different damping specifications.  Damping ratio is equal to (Loss Tangent) \/ 2.  You can also see that in Theory Manual EQ 15-21.  Damping input with TB,SDAMP (loss tangent) is multiplied by 1\/OMEGA, damping input with MP,DMPR (damping ratio) is multiplied by 2\/OMEGA.  Note that in a harmonic analysis, damping ratio is not a constant ratio to critical.  For a single mode it would be ratio to critical at resonance but become a smaller ratio to critical at lower frequencies and a higher ratio at higher frequencies.  This effect isn&#8217;t very noticeable because the effect of damping decreases quickly away from resonance.<\/p>\n","protected":false},"template":"","class_list":["post-167207","topic","type-topic","status-publish","hentry","topic-tag-4457","topic-tag-mechanical-apdl-f-ansys","topic-tag-modal-harmonic-response","topic-tag-structural-dynamics","topic-tag-structural-mechanics"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_wp_page_template":["default"],"_bbp_last_active_time":["5\/4\/2023 20:20"],"_bbp_forum_id":["27792"],"_bbp_author_ip":["209.182.204.162"],"_btv_view_count":["766"],"siebel_km_number":["2025869"],"product_version":["14"],"km_published_date":["2012-10-13T00:00:00.000Z"],"family":["Structural Mechanics"],"application_name":["Mechanical APDL (f. ANSYS)"]},"test":"articlesansys-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/167207","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/167207\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/media?parent=167207"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}