{"id":346810,"date":"2024-01-26T17:12:25","date_gmt":"2024-01-26T17:12:25","guid":{"rendered":"\/forum\/forums\/topic\/d3-failure-parameter-in-mat_015-johnson_cook\/"},"modified":"2024-01-26T17:12:25","modified_gmt":"2024-01-26T17:12:25","slug":"d3-failure-parameter-in-mat_015-johnson_cook","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/d3-failure-parameter-in-mat_015-johnson_cook\/","title":{"rendered":"D3 failure parameter in *MAT_015 (JOHNSON_COOK)"},"content":{"rendered":"<p>Hello,<\/p>\n<p>I find that in the LS-DYNA manual 2, the failure parameters are described below:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/26-01-2024-1706288634-mceclip0.png\"><\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/26-01-2024-1706289058-mceclip2.png\"><\/p>\n<p>The D3 will be converted to a positive value if the input is negative. However, in the papers to calculate these parameters, they fit the JC formula and always obtained a negative D3 parameter, such as:<\/p>\n<p><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/26-01-2024-1706288898-mceclip1.png\"><\/p>\n<p>So, I would like to know why LS-DYNA has to convert the negative D3 to its absolute value? Is it because the definition of pressure or effective stress in LS-DYNA is different?<\/p>\n<p>&nbsp;<\/p>\n<p>Best,<\/p>\n<p>Rong<\/p>\n","protected":false},"template":"","class_list":["post-346810","topic","type-topic","status-closed","hentry","topic-tag-ls-dyna","topic-tag-material-properties"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["22672","275204"],"_bbp_author_ip":["96.7.218.215"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1827"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["346810"],"_bbp_forum_id":["27814"],"_bbp_engagement":["22672","275204"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["347082"],"_bbp_last_active_id":["347082"],"_bbp_last_active_time":["2024-01-29 16:57:25"]},"test":"rji229uky-edu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/346810","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\/346810\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=346810"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}