{"id":370321,"date":"2024-07-03T14:11:41","date_gmt":"2024-07-03T14:11:41","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/excessive-thickness-change-error-in-2-way-fsi-2\/"},"modified":"2024-07-23T14:33:44","modified_gmt":"2024-07-23T14:33:44","slug":"excessive-thickness-change-error-in-2-way-fsi-2","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/excessive-thickness-change-error-in-2-way-fsi-2\/","title":{"rendered":"“Excessive Thickness Change” Error in 2 way FSI"},"content":{"rendered":"
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I am running a two-way FSI involving blood and vessel, but I encounter excessive thickness change problem. I can only obtain results when using a very high Young’s modulus (10,000 MPa). Despite this, the simulation does not converge consistently; sometimes it converges, and other times it does not. (time step= 0.001)<\/p>\n

I want to perform the simulation using actual values for the vessel, which means using a lower Young’s modulus, around 0.05 MPa<\/strong>. However, when I do this, the simulation crashes immediately with the following error message: “Element xxx has excessive thickness change<\/strong>“.<\/p>\n

I am confident that the fluid part of the simulation (Fluent) works well even without FSI, but the structural part keeps crashing when I use the lower Young’s modulus. I know that people are simulating blood flow in vessels without any errors, but I am unsure how to fix this issue. <\/p>\n

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I have seen this question frequently asked by users, but no answer has been provided, so I hope someone can help me resolve this problem. Thanks!<\/p>\n

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Edit (Rob) – cleaning up posts. <\/p>\n

I am running a two-way FSI  involving blood and vessel, but I encounter this error “excessive thickness change”.<\/em><\/p>\n

I can only obtain results when using a very high Young’s modulus (10,000 MPa). Despite this, the simulation does not converge consistently; sometimes it converges, and other times it does not.<\/em><\/p>\n

I want to perform the simulation using actual values for the vessel, which means using a lower Young’s modulus, around E_Vessel=0.05 MPa<\/strong>. However, when I do this, the simulation crashes immediately with the following error message: “(DP 0) Participant Solution encountered a fatal error. Message: Element 248 has excessive thickness change. Please do not save the project if you would like to recover to the last saved state.<\/strong>” <\/em><\/p>\n

I am confident that the fluid part of the simulation (Fluent) works well even without FSI, but the structural part keeps crashing when I use the lower Young’s modulus. I know that people are simulating blood flow in vessels without any errors, but I am unsure how to fix this issue.<\/em><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"template":"","class_list":["post-370321","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_btv_view_count":["752"],"_bbp_topic_status":["answered"],"_edit_lock":["1720016495:199"],"_bbp_subscription":["805","431728","88"],"_bbp_notification_enabled":["431728","431728"],"_bbp_topic_id":["370321"],"_bbp_forum_id":["27792"],"_bbp_engagement":["88","805","431728"],"_bbp_voice_count":["3"],"_bbp_last_reply_id":["373266"],"_bbp_last_active_id":["373266"],"_bbp_last_active_time":["2024-07-23 14:34:09"]},"test":"751ef47ef94a7db2035eda1dd10abecb4b252174"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/370321","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\/370321\/revisions"}],"predecessor-version":[{"id":370332,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/370321\/revisions\/370332"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=370321"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}