{"id":456778,"date":"2026-04-20T17:31:34","date_gmt":"2026-04-20T17:31:34","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/tungsen-impact\/"},"modified":"2026-04-20T17:31:34","modified_gmt":"2026-04-20T17:31:34","slug":"tungsen-impact","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/tungsen-impact\/","title":{"rendered":"Tungsen impact"},"content":{"rendered":"<p>&lt;p&gt;Hello,&nbsp;&lt;\/p&gt;&lt;p&gt;I&#8217;m trying to modelize high velocity impacts of tungsten balls on tungsten plates, with ranges from 600 to 4000m\/s (subhypervelocity). Given the speed, I&#8217;d like to use Johnson Cook or Modified Zerilli Armstrong cards, but whenever I use them without the MAT_ADD_EROSION, I have either a non physical behavior (with ELFORM 1), or negative volume issues (ELFORM 2). If I add the MAT_ADD_EROSION card, the ball erodes too much if I use the criteria given in the litterature. Am I on the wrong path ? Are the EFFEPS, MXEPS, MINEPS dependent of the size of the mesh? Do you have any tips ?&nbsp;&lt;\/p&gt;&lt;p&gt;Thanks for you answers!&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-456778","topic","type-topic","status-publish","hentry","topic-tag-crash-test","topic-tag-negative-volume","topic-tag-strain-rate"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["456778"],"_bbp_subscription":["634361","13640"],"_bbp_author_ip":["80.217.65.158"],"_bbp_last_reply_id":["456835"],"_bbp_last_active_id":["456835"],"_bbp_last_active_time":["2026-04-21 13:00:01"],"_bbp_reply_count":["1"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["634361","13640"],"_btv_view_count":["76"],"_bbp_topic_status":["unanswered"],"_edit_lock":["1776845665:634361"]},"test":"noe-lacombestudent-isae-supaero-fr"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/456778","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\/456778\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=456778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}