{"id":166026,"date":"2022-02-02T01:43:12","date_gmt":"2022-02-02T01:43:12","guid":{"rendered":"\/forum\/forums\/topic\/fracture-package-errors\/"},"modified":"2022-03-27T22:00:11","modified_gmt":"2022-03-27T22:00:11","slug":"fracture-package-errors","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fracture-package-errors\/","title":{"rendered":"Fracture Package errors"},"content":{"rendered":"
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I am trying to use ANSYS's fracture package to solve a fatigue crack growth problem – a fairly simple one for now. The model is a fairly standard notched tensile sample geometry with isotropic linear-elastic aluminum. I am using a Pre-meshed Crack object in the analysis. So far, I have encountered 2 issues.<\/p>\n

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  1. Solving the problem with just the Pre-meshed Crack defined gives me an incorrect answer for K1 (the primary stress intensity factor mode). It is a simple geometry, so I have a good analytical answer to compare. It is off by an order of magnitude. The stress in the part is correct; I don't know why the SIF isn't. It seems insensitive to mesh refinement.<\/li>\n
  2. If I add a SMART Crack Growth object and set the Crack Growth Option to 'Fatigue', the solver crashes when reaches the "Calculating Fracture results" step. The error message in the Solver Output reads "For Cgrow Id 1 and Crack Id 1, the computed number of cycles is less than 1. Under this loading condition, static crack growth is expected. Please check your model, boundary conditions, and fatigue parameters. The crack growth solve is stopped." To thicken the plot, if I set Crack Growth Option to 'Static', the crack extension probe shows zero crack growth, and the SIFS (K1) result now returns the correct answer that it didn't return in 1.<\/li>\n<\/ol>\n

    My questions are:<\/p>\n

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    1. Any insight as to why I am not getting a correct SIF result without the SMART Crack Growth object?<\/li>\n
    2. What might be causing the error message when I try to run the fatigue model? I'm relatively confident in my Paris Law coefficients, but I can't think of what else it could be and the error message hasn't changed despite trying a wide range of values.<\/li>\n
    3. Are there any good resources floating around, especially working models with the SMART Crack Growth object? This site and Youtube seem thin.<\/li>\n<\/ol>\n

      Thanks in advance for any help!<\/p>\n","protected":false},"template":"","class_list":["post-166026","topic","type-topic","status-closed","hentry","topic-tag-fracture","topic-tag-paris-law-1","topic-tag-pre-meshed-crack-1","topic-tag-sif-1","topic-tag-smart-crack-growth"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_btv_view_count":["3365"],"_bbp_likes_count":["0"],"_bbp_subscription":["247125","260788"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["166026"],"_bbp_forum_id":["27791"],"_bbp_engagement":["157520","247125","248628","260788"],"_bbp_voice_count":["4"],"_bbp_reply_count":["6"],"_bbp_last_reply_id":["222634"],"_bbp_last_active_id":["222634"],"_bbp_last_active_time":["2022-07-29 03:09:00"]},"test":"tommy-clecknergmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/166026","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\/166026\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=166026"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}