{"id":453945,"date":"2026-03-08T09:59:03","date_gmt":"2026-03-08T09:59:03","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/stress-values-looks-weird-on-johnson-cook-material-model\/"},"modified":"2026-03-08T09:59:03","modified_gmt":"2026-03-08T09:59:03","slug":"stress-values-looks-weird-on-johnson-cook-material-model","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/stress-values-looks-weird-on-johnson-cook-material-model\/","title":{"rendered":"Stress Values Looks Weird on Johnson Cook Material Model"},"content":{"rendered":"<p>&lt;p&gt;Hello everyone&lt;\/p&gt;&lt;p&gt;I&#8217;m working on a ballistic analysis on Ls-Dyna. Before I do my own simulations I&#8217;m trying to replicate an article right now. In that article a rigid ball smashes into a aluminum armor plate. Material model for aluminum is Johnson Cook and the values of it were given in article but when I run the simulation stress values looks weird. For instance X,Y and Z stress values all looks the same, there is NO shear stress whatsoever, there are only small dots of stress in von mises and tresca stress, effective plastic strain is non-existant and the bulge that appears when the ball penetrates through the armor seems too big. What could be causes of this? When I use simplified johnson cook model stress and strain values looks fine but when I switch to normal johnson cook everything looks wrong. Can somebody help please??? Pictures of my problem are in the link:&nbsp;<a title=\"Images\" href=\"https:\/\/imgur.com\/a\/nTRUaSL\" target=\"_blank\" rel=\"noopener\">https:\/\/imgur.com\/a\/nTRUaSL<\/a>&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-453945","topic","type-topic","status-publish","hentry","topic-tag-ansys-ls-dyna-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["453945"],"_bbp_subscription":["578569","13640","58821"],"_bbp_author_ip":["5.47.200.185"],"_bbp_last_reply_id":["453966"],"_bbp_last_active_id":["453966"],"_bbp_last_active_time":["2026-03-09 08:49:23"],"_bbp_reply_count":["2"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["3"],"_bbp_engagement":["578569","13640","58821"],"_btv_view_count":["89"],"_bbp_topic_status":["unanswered"]},"test":"yvzslm48gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/453945","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\/453945\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=453945"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}