{"id":159920,"date":"2021-06-28T13:28:30","date_gmt":"2021-06-28T13:28:30","guid":{"rendered":"\/forum\/forums\/topic\/update-of-the-stiffness-matrix-by-the-newton-raphson-method\/"},"modified":"2021-06-29T13:39:33","modified_gmt":"2021-06-29T13:39:33","slug":"update-of-the-stiffness-matrix-by-the-newton-raphson-method","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/update-of-the-stiffness-matrix-by-the-newton-raphson-method\/","title":{"rendered":"Update of the stiffness matrix by the Newton Raphson method"},"content":{"rendered":"<div class=\"Item-Body\">\n<div class=\"Message userContent\">\n<p>Hello to all,<\/p>\n<p><\/p>\n<\/p>\n<p>I would like to ask for your expertise on finite elements in order to know how to make the right choice on the different methods of solving the finite element calculation.<\/p>\n<p><\/p>\n<\/p>\n<p>In Ansys, the resolution of the equation K*U=F is done by the Newton-Raphson method. Several resolution techniques exist, among them: the full, asymmetric and modified Newton-Raphson method (respectively NROPT,full NROPT,unsym NROPT,modi).<\/p>\n<p><\/p>\n<p><\/p>\n<p><\/p>\n<\/p>\n<p>&nbsp;The difference in its resolutions is that for the first two methods, the stiffness matrix is updated at each iteration contrary to the last one which updates the stiffness matrix only on the first iterations (so there is less inversion of the matrix and less formulation). The final choice of these two methods could be done by what means? (we can always proceed by scanning the cases and see the difference of the results, which can be long I think)<\/p>\n<p><\/p>\n<\/p>\n<p>&nbsp;Are there some structures that require an update of the stiffness matrix at each iteration (I guess yes as for hyperelastic materials) and others not? If the stiffness matrix is not updated at each iteration the accuracy is not the same I think, so the last method of solving should not exist?<\/p>\n<p>thank,<\/p>\n","protected":false},"template":"","class_list":["post-159920","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["2569"],"_bbp_likes_count":["0"],"_bbp_subscription":["248608"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["159920"],"_bbp_forum_id":["27791"],"_bbp_engagement":["174388","185297"],"_bbp_voice_count":["2"],"_bbp_reply_count":["2"],"_bbp_last_reply_id":["183761"],"_bbp_last_active_id":["183761"],"_bbp_last_active_time":["2021-06-29 13:39:33"]},"test":"brivael"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/159920","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\/159920\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=159920"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}