


{"id":32281,"date":"2018-12-22T13:44:58","date_gmt":"2018-12-22T13:44:58","guid":{"rendered":"\/forum\/forums\/topic\/convergence-difficulties-due-to-abrupt-stiffness-change-ekill\/"},"modified":"2018-12-22T13:44:58","modified_gmt":"2018-12-22T13:44:58","slug":"convergence-difficulties-due-to-abrupt-stiffness-change-ekill","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/convergence-difficulties-due-to-abrupt-stiffness-change-ekill\/","title":{"rendered":"Convergence difficulties due to abrupt stiffness change (ekill)"},"content":{"rendered":"<p>Hello everybody<\/p>\n<p><\/p>\n<p>I am running a nonlinear structural simulation with multiframe restart option in Ansys APDL of a sandwich structure which is loaded via a displacement control. After each load step I postprocess relevant data to know, if a core element during the simulation fails. If such a core element fails then I restart the simulation from the previous substep and kill the elements which failed with the ekill command. Problem is that, after deactivating the failed elements the simulation does not converge anymore. NROPT,full,,on has been set and also the time increment respectively the displacement increment has been chosen very small. Nevertheless no improvement of the convergence has been achieved. The problem of course is that the stiffness becomes very low after deactivating the failed elements. What I also tried is a simulation without the failed elements from the beginning but then the simulation converges and also a very large displacement and reaction force is achieved, which means that the before mentioned calculation should be possible, but I really do not know how to overcome the convergence difficulties.<\/p>\n<p><\/p>\n<p>I would be very happy for any suggestions I could try.<\/p>\n<p><\/p>\n<p>Thanks a lot.<\/p>\n<p><\/p>\n<p>Best regards<\/p>\n<p><\/p>\n<p>El Cid<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-32281","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["4453"],"_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","0","0","0","0"],"_btv_view_count":["1448"],"_bbp_subscription":["238084"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["32281"],"_bbp_forum_id":["27791"],"_bbp_engagement":["897","110894","160648","160977"],"_bbp_voice_count":["4"],"_bbp_reply_count":["6"],"_bbp_last_reply_id":["94927"],"_bbp_last_active_id":["94927"],"_bbp_last_active_time":["2019-09-26 07:25:37"]},"test":"elcid01"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/32281","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\/32281\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=32281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}