{"id":43960,"date":"2020-05-13T19:17:38","date_gmt":"2020-05-13T19:17:38","guid":{"rendered":"\/forum\/forums\/topic\/distortion-and-convergence-problems-with-simple-elastic-plate\/"},"modified":"2020-05-13T19:17:38","modified_gmt":"2020-05-13T19:17:38","slug":"distortion-and-convergence-problems-with-simple-elastic-plate","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/distortion-and-convergence-problems-with-simple-elastic-plate\/","title":{"rendered":"Distortion and Convergence Problems with Simple Elastic Plate"},"content":{"rendered":"

I have a simple plate made of a linearly elastic material, that is fixed on top and has a force acting on it from the side. I want to have a very soft material and large deformation.<\/p>\n

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For quicker testing, I used a very coarse mesh.<\/p>\n

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I need to use fixed time step. I tried out some step sizes.<\/p>\n

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With step size 0.01 sec, this error occurs instantly:<\/p>\n

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Element 1 located in Body “SYSSolid” (and maybe other elements) has become highly distorted.  You may select the offending object and\/or geometry via RMB on this warning in the Messages window.  Excessive distortion of elements is usually a symptom indicating the need for corrective action elsewhere.  Try incrementing the load more slowly (increase the number of substeps or decrease the time step size).  You may need to improve your mesh to obtain elements with better aspect ratios.  Also consider the behavior of materials, contact pairs, and\/or constraint equations.  If this message appears in the first iteration of first substep, be sure to perform element shape checking. Named Selections for the offending element can be created via the Identify Element Violations property on the Solution Information Object.<\/p>\n

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Also the solution has not converged. Total Deformation output:<\/p>\n

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With step size 0.0001 sec, the simulation stops converging at step 167.<\/p>\n

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The shape has not even much deformed yet. Shown below is Total Deformation of latest result.<\/p>\n

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With step size 0.00001 sec, it stops converging after step 4238 and still not much deformation.<\/p>\n

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So I now reach 0.042 real time seconds instead of 0.017, but I have a ten times smaller step size and the simulation took about half an hour instead of ten minutes. It did not seem reasonable to me to keep reducing the step size.<\/p>\n

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I have Large Deflection turned on.<\/p>\n

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Please take into account that I am a complete novice and may have set an unphysical material or loading or such a bad mesh that it can not work.<\/p>\n

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How can I know, how small does the time step have to be?<\/p>\n

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Are there other ways to improve stability of the simulation?<\/p>\n

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Can I expect a case like this to simulate one real time second in less than ten minutes on a 2018 AMD Ryzen 6 Core processor?<\/p>\n

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If the error is in my setup: Can one calculate from the linearly elastic material what force is needed for a certain amount of deflection?<\/p>\n","protected":false},"template":"","class_list":["post-43960","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["16141"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["1112"],"_bbp_subscription":["245163"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["43960"],"_bbp_forum_id":["27791"],"_bbp_engagement":["240","170807"],"_bbp_voice_count":["2"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["114830"],"_bbp_last_active_id":["114830"],"_bbp_last_active_time":["2020-05-18 10:47:32"]},"test":"mskr"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/43960","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\/43960\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=43960"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}