{"id":381561,"date":"2024-09-04T16:48:28","date_gmt":"2024-09-04T16:48:28","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/coupled-field-harmonic-analysis-with-pretension\/"},"modified":"2024-09-04T16:48:28","modified_gmt":"2024-09-04T16:48:28","slug":"coupled-field-harmonic-analysis-with-pretension","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/coupled-field-harmonic-analysis-with-pretension\/","title":{"rendered":"coupled field harmonic analysis with pretension"},"content":{"rendered":"<p>&lt;div class=&#8221;x_elementToProof&#8221;&gt;I am currently working on a simulation in ANSYS Workbench involving a coupled field static analysis followed by a coupled field harmonic analysis. I model two piezoelectric actuators near each side of a string. I encountered an issue that I need assistance with.&lt;\/div&gt;&lt;div&gt;<strong>Problem Description:<\/strong>&lt;\/div&gt;<\/p>\n<ul>\n<li>&lt;div class=&#8221;x_elementToProof&#8221;&gt;In the first step, I performed a coupled field static analysis where I applied a displacement boundary condition at one end of a string and a fixed boundary condition at the other end (pretension of string). I also applied voltages to the piezoelectric actuators attached to the beam.&lt;\/div&gt;<\/li>\n<li>&lt;div class=&#8221;x_elementToProof&#8221;&gt;I then linked the solution from this static analysis to a coupled field harmonic analysis setup. I intended&nbsp;for the string to maintain its static displacement while the piezoelectric actuators actuate harmonically.&lt;\/div&gt;<\/li>\n<\/ul>\n<p>&lt;div&gt;<strong>Issue:<\/strong>&lt;\/div&gt;&lt;div class=&#8221;x_elementToProof&#8221;&gt;When I check the harmonic analysis results, it appears that the displacement boundary condition from the static analysis is being treated as a harmonic load. As a result, the sting is stretching and shortening in cycles, which is not the intended behaviour. Instead, I want the string to first stretch as per the static analysis and then remain in that state while only the piezoelectric actuators function during the harmonic analysis.&lt;\/div&gt;&lt;div&gt;<strong>Request for Guidance:<\/strong>&lt;\/div&gt;&lt;div&gt;Could you please advise on how to correctly configure the boundary conditions so that the displacement from the static analysis acts as a constant initial condition in the harmonic analysis, without turning into a varying harmonic load?&lt;\/div&gt;&lt;div class=&#8221;x_elementToProof&#8221;&gt;<strong>I selected different options (&#8216;keep all&#8217;, &#8216;keep inertia and displacement constraints&#8217;, &#8216;keep displacement constraints&#8217;) in the &#8216;load control&#8217; section in the Pre-stress section of coupled field harmonic analysis. But they do not work and still, I see the harmonical movement of string in the z-direction (longitudinal) in the directional deformation results, which is wrong.<\/strong>&lt;\/div&gt;&lt;div class=&#8221;x_elementToProof&#8221;&gt;please kindly see the attached picture.&lt;\/div&gt;&lt;div class=&#8221;x_elementToProof&#8221;&gt;I would greatly appreciate any insights or guidance you can provide to resolve this issue.&lt;\/div&gt;&lt;div class=&#8221;x_elementToProof&#8221;&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/09\/04-09-2024-1725468175-directional deformation.png\" alt=\"\" \/>&lt;\/div&gt;<\/p>\n","protected":false},"template":"","class_list":["post-381561","topic","type-topic","status-publish","hentry","topic-tag-coupled-field-1","topic-tag-harmonic","topic-tag-mechanical","topic-tag-preload","topic-tag-simulation"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["290506","20905","58821"],"_bbp_author_ip":["152.71.146.36"],"_btv_view_count":["577"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["381561"],"_bbp_forum_id":["27791"],"_bbp_engagement":["20905","58821","290506"],"_bbp_voice_count":["3"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["381916"],"_bbp_last_active_id":["381916"],"_bbp_last_active_time":["2024-09-09 08:56:17"]},"test":"n1129070my-ntu-ac-uk"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/381561","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\/381561\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=381561"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}