{"id":248696,"date":"2023-02-06T09:53:45","date_gmt":"2023-02-06T09:53:45","guid":{"rendered":"\/forum\/forums\/topic\/program-controlled-normal-stiffness-when-to-use-and-when-to-override\/"},"modified":"2023-02-06T09:53:45","modified_gmt":"2023-02-06T09:53:45","slug":"program-controlled-normal-stiffness-when-to-use-and-when-to-override","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/program-controlled-normal-stiffness-when-to-use-and-when-to-override\/","title":{"rendered":"Program controlled normal stiffness &#8211; When to use and when to override?"},"content":{"rendered":"<p>Hello All,<\/p>\n<p>In penalty based contact formulations (augmented lagrange and pure penalty), when should we use &#8220;program controlled&#8221; stiffness vs when to override using a stiffness factor?<\/p>\n<p>Current forum answers\/literature suggests to use lower stiffness factor values (0.1 to 1) to soften the contact and overcome convergence issues. The only rule of thumb that keeps repeating in all literature and ansys help is &#8220;use high enough stiffness so that no convergence issues happen&#8221;.<\/p>\n<p>So if there are no convergence issues with &#8216;program controlled&#8217; stiffness, we should never override stiffness?<\/p>\n<p>I also noticed that similar element size &#8216;tetrahedral&#8217; elements at contact generate higher contact pressure compared to &#8216;hexahedral&#8217; elements (in my trials, i noticed that hexahedral elements showed good correlation with theoretical contact pressure calculations based on hertz theory, with program controlled stiffness). Any thoughts on the same?<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-248696","topic","type-topic","status-closed","hentry","topic-tag-contact"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["265176","13386","240"],"_bbp_author_ip":["96.7.74.191"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["5100"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["248696"],"_bbp_forum_id":["27791"],"_bbp_engagement":["240","13386","265176"],"_bbp_voice_count":["3"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["275319"],"_bbp_last_active_id":["275319"],"_bbp_last_active_time":["2023-03-17 14:15:01"]},"test":"vinay-k-mamidalamedtronic-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/248696","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\/248696\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=248696"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}