{"id":216633,"date":"2022-06-23T06:51:34","date_gmt":"2022-06-23T06:51:34","guid":{"rendered":"\/forum\/forums\/topic\/multilinear-isotropic-hardening-2\/"},"modified":"2022-06-23T06:51:34","modified_gmt":"2022-06-23T06:51:34","slug":"multilinear-isotropic-hardening-2","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/multilinear-isotropic-hardening-2\/","title":{"rendered":"Multilinear Isotropic Hardening"},"content":{"rendered":"

Hello, <\/span><\/p>\n

I <\/span>want<\/span> to <\/span>perform<\/span> a <\/span>analysis<\/span> of a <\/span>component<\/span> <\/span>using<\/span> <\/span>Plasticity<\/span><\/strong>. <\/span><\/p>\n

I’ve<\/span> <\/span>have<\/span> a <\/span>stress-strain<\/span> <\/span>curve<\/span> from MMPDS, <\/span>see<\/span> <\/span>attached<\/span> image. According to MMPDS, the <\/span>curve<\/span> is a <\/span>Engineering<\/span> <\/span>Stress-Strain<\/span>.<\/span><\/p>\n

We<\/span> <\/span>have<\/span> <\/span>used<\/span> <\/span>similar<\/span> <\/span>analysis<\/span> a long <\/span>time<\/span> <\/span>ago<\/span>, <\/span>but<\/span> <\/span>that<\/span> <\/span>was<\/span> in Ansys R15.0. <\/span>However<\/span>, in <\/span>that<\/span> version, the Total <\/strong><\/span>Strain<\/span> <\/span>was<\/span> <\/span>entered<\/span> <\/span>instead<\/span> of Plastic <\/span>Strain<\/span><\/strong>, <\/span>see<\/span> <\/span>attached<\/span> image. <\/span><\/p>\n

I’ve<\/span> <\/span>some<\/span> <\/span>questions<\/span> <\/span>regarding<\/span> <\/span>this<\/span>; <\/span>especially<\/span> <\/span>about<\/span> <\/span>preparding<\/span> the <\/span>correct<\/span> table to input in Ansys<\/span><\/p>\n

1. Ramberg-<\/strong><\/span>Osgood<\/span> <\/span>Equation<\/span><\/strong>: I <\/span>have<\/span> E, <\/span>Fty<\/span> and n (<\/span>see<\/span> <\/span>attached<\/span> image), so I <\/span>simply<\/span> try to <\/span>create<\/span> a <\/span>lot<\/span> of <\/span>stress-strain<\/span> <\/span>values<\/span> from <\/span>this<\/span> <\/span>equation<\/span> <\/span>using<\/span> <\/span>this<\/span> parameters, <\/span>but<\/span> I <\/span>don’t<\/span> get the <\/span>correct<\/span> <\/span>values<\/span>. Is the <\/strong><\/span>method<\/span> <\/span>correct<\/span><\/strong>? <\/strong>In the second <\/span>attached<\/span> image, I show my <\/span>values<\/span> from <\/span>this<\/span> <\/span>equation<\/span> <\/span>and parameters. According to the <\/span>graph<\/span>, 169ksi <\/span>should<\/span> <\/span>give<\/span> ~0.011, <\/span>but<\/span> I get ~0.085, so <\/span>I’m<\/span> <\/span>way<\/span> off. <\/span>Cannot<\/span> <\/span>find<\/span> <\/span>out<\/span> <\/span>why<\/span>. <\/span><\/p>\n

2<\/span>. According to [<\/span>https:\/\/<\/a><\/span>www.youtube.com\/watch?v=rCFmcNWRds4<\/a><\/span>], <\/span>True<\/span> <\/span>Stress-Strain<\/span> is <\/span>required<\/span>; <\/span>should<\/span> I <\/span>convert<\/span> from Engineering to <\/span>True<\/span> <\/span>stress-strain<\/span> <\/span>using<\/span> the <\/span>equations<\/span> in <\/span>attached<\/span> image and <\/span>then<\/span> <\/span>subtract<\/span> the <\/span>elastic<\/span> <\/span>strain<\/span> (s\/E) to <\/span>only<\/span> get the plastic <\/span>strain<\/span>?<\/span><\/p>\n

3<\/span>. <\/span>According to [<\/span>https:\/\/www.youtube.com\/watch?v=rCFmcNWRds4<\/a><\/span>], <\/span>the <\/span>first<\/span> point <\/span>should<\/span> be (0, <\/span>yield<\/span> <\/span>strength<\/span>), <\/span>but<\/span> <\/span>how<\/span> <\/span>should<\/span> I <\/span>then<\/span> <\/span>include<\/span> 0.2% plastic <\/span>strain<\/span> at <\/span>yield<\/span> point?<\/span> <\/span>There<\/span> is a parameter <\/span>called<\/span> <\/span>Offset<\/span>, <\/span>but<\/span> I <\/span>cannot<\/span> <\/span>modify<\/span> the <\/span>values<\/span>. <\/span>Should<\/span> <\/span>this<\/span> parameter be <\/span>used<\/span> <\/span>somehow<\/span>?<\/span><\/p>\n

Regards<\/span>,<\/span><\/p>\n

Albin<\/span>\"\"<\/p>\n

 <\/p>\n

\"\"<\/p>\n","protected":false},"template":"","class_list":["post-216633","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["25148","58821"],"_bbp_author_ip":["23.218.93.111"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["2222"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["216633"],"_bbp_forum_id":["27791"],"_bbp_engagement":["25148","58821"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["216659"],"_bbp_last_active_id":["216659"],"_bbp_last_active_time":["2022-06-23 09:51:14"]},"test":"albin-linderstamsaabgroup-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/216633","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\/216633\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=216633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}