{"id":162208,"date":"2023-01-25T07:34:37","date_gmt":"2023-01-25T07:34:37","guid":{"rendered":"\/knowledge\/forums\/topic\/is-it-possible-to-directly-apply-an-acceleration-or-a-velocity-load-in-a-harmonic-analysis\/"},"modified":"2023-07-31T12:36:35","modified_gmt":"2023-07-31T12:36:35","slug":"is-it-possible-to-directly-apply-an-acceleration-or-a-velocity-load-in-a-harmonic-analysis","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/is-it-possible-to-directly-apply-an-acceleration-or-a-velocity-load-in-a-harmonic-analysis\/","title":{"rendered":"Is it possible to directly apply an acceleration or a velocity load in a harmonic analysis?"},"content":{"rendered":"<p>No.  The acceleration and velocity constraints (D,ACCX and D,VELX, respectively) are valid only for structural static and transient analyses (Basic Guide, Section 2.5). In a harmonic analysis all loads are assumed to vary sinusoidally.  You need to integrate the acceleration\/velocity load and apply it as a displacement.  The integration only requires a simple division.  acceleration load (a = acceleration, v = velocity, u = displacement, w = omega = frequency, t = time):  a = A sin (wt)  v = A\/w cos (wt)  u = -A\/w\/w sin (wt)  As a result, to apply an acceleration load of magnitude &#8220;A&#8221;, simply set a displacement constraint with a magnitude of &#8220;-A\/w\/w&#8221;.<\/p>\n","protected":false},"template":"","class_list":["post-162208","topic","type-topic","status-publish","hentry","topic-tag-4653","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_forum_id":["27792"],"_bbp_last_active_time":["1-24-2023  20:20:14"],"_bbp_author_ip":["23.56.168.180"],"_btv_view_count":["3439"],"siebel_km_number":["788686"],"product_version":["11"],"km_published_date":["2008-08-07T10:20:31.000Z"],"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\/162208","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\/162208\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/media?parent=162208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}