{"id":165475,"date":"2023-03-17T09:00:25","date_gmt":"2023-03-17T09:00:25","guid":{"rendered":"\/knowledge\/forums\/topic\/for-a-simulation-using-hyperelastic-materials-when-i-compare-my-ansys-mapdl-or-workbench-mechanical-stress-strain-output-graph-to-my-input-stress-strain-graph-they-do-not-match-why\/"},"modified":"2023-07-31T12:31:20","modified_gmt":"2023-07-31T12:31:20","slug":"for-a-simulation-using-hyperelastic-materials-when-i-compare-my-ansys-mapdl-or-workbench-mechanical-stress-strain-output-graph-to-my-input-stress-strain-graph-they-do-not-match-why","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/for-a-simulation-using-hyperelastic-materials-when-i-compare-my-ansys-mapdl-or-workbench-mechanical-stress-strain-output-graph-to-my-input-stress-strain-graph-they-do-not-match-why\/","title":{"rendered":"For a simulation using hyperelastic materials, when I compare my ANSYS (MAPDL or Workbench Mechanical) Stress\/Strain output graph to my input Stress\/Strain graph, they do not match.  Why?"},"content":{"rendered":"<p>For hyperelastic materials, the material Stress\/Strain data that is input is the Engineering Stress\/Strain.  The ANSYS output, on the other hand, is True Stress\/Strain. So, the user will need to convert the ANSYS output from True Stress\/Strain to Engineering Stress\/Strain when comparing the input material curve and output Stress\/Strain curves.  Formulae to be used:  Convert ANSYS Output True Strain to Engineering Strain: Engineering Strain = EXP(True Strain) &#8211; 1  Convert ANSYS Output True Stress to Engineering Stress: Engineering Stress = True Stress\/(1+Engineering Strain)<\/p>\n","protected":false},"template":"","class_list":["post-165475","topic","type-topic","status-publish","hentry","topic-tag-4670","topic-tag-hyperelasticity","topic-tag-materials","topic-tag-mechanical-f-simulation","topic-tag-structural-mechanics"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_wp_page_template":["default"],"_bbp_last_active_time":["3\/15\/2023 20:20"],"_bbp_forum_id":["27814"],"_bbp_author_ip":["23.56.168.180"],"_btv_view_count":["1204"],"siebel_km_number":["2021882"],"product_version":["13"],"km_published_date":["2011-11-23T00:00:00.000Z"],"family":["Structural Mechanics"],"application_name":["Mechanical (f. Simulation)"]},"test":"articlesansys-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/165475","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/165475\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/media?parent=165475"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}