{"id":36780,"date":"2019-07-26T14:37:51","date_gmt":"2019-07-26T14:37:51","guid":{"rendered":"\/forum\/forums\/topic\/updatting-normal-stiffness\/"},"modified":"2019-07-26T14:37:51","modified_gmt":"2019-07-26T14:37:51","slug":"updatting-normal-stiffness","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/updatting-normal-stiffness\/","title":{"rendered":"Updatting Normal Stiffness"},"content":{"rendered":"<p><strong>Hello Everyone,<\/strong><\/p>\n<p><\/p>\n<p>I&nbsp;have a question about updating normal stiffness. In my&nbsp;model I have bone-screw&nbsp;contact. Screws&nbsp;are modeled as cylinders and have bonded contact with bone holes. Because in the reality there are some penetrations between spongy bone and screws, I assumed the&nbsp;Pure Penalty Bonded contact with normal stiffness factor 1. Then for these contacts updating stiffness option was selected as never, and for&nbsp; the rest frictional or bonded contacts updating&nbsp;stiffness was set to&nbsp;in each iterartion. Now the question is that why did total displacement (displacement of loading center) reduce? Because by default&nbsp;normal stiffness factor of bonded contact is 10 and selecting lower values and never updating should reduce global stiffness of our system and displacement should increase. Hence, I am confused a little bit about the&nbsp;differences between updating&nbsp;normal stiffness in each iteration or never. Because on the one hand, we reduce contact normal stiffness factor for convergency, but on the other hand it is recommended to use update stiffness in each iteration to allow the software to change normal stiffness according&nbsp;to stress and penetration values in contact area. Hence, what is the role of small normal stiffness factor when it will be later changed by the software? When we have different contact types with different normal stiffness values, how does&nbsp;work updating&nbsp;stiffness option? Does it take a global normal stiffness value for all contacts&nbsp; in each iteration?<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/d2105cd9-d9ac-4d64-959e-aa7a00a02f47\/67b3f715-72de-4aaa-8577-aa9600efae83_bild1.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/d2105cd9-d9ac-4d64-959e-aa7a00a02f47\/fb4686b3-e86a-4e1c-8e76-aa9600f0430e_bild0.jpg?width=690&amp;upscale=false\" alt=\"Area with Bonded Contact of K=1\"><\/p>\n<p><\/p>\n<p>I am grateful if someone can advise me in this regard.<\/p>\n<p><\/p>\n<p><strong>Best regards, Shabnam Samsami<\/strong><\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-36780","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["8954"],"_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"],"_btv_view_count":["5186"],"_bbp_subscription":["241047"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["36780"],"_bbp_forum_id":["27791"],"_bbp_engagement":["22","166380"],"_bbp_voice_count":["2"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["91049"],"_bbp_last_active_id":["91049"],"_bbp_last_active_time":["2019-08-01 14:07:00"]},"test":"royalflowers"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/36780","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\/36780\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=36780"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}