{"id":301750,"date":"2023-08-16T18:06:40","date_gmt":"2023-08-16T18:06:40","guid":{"rendered":"\/forum\/forums\/reply\/301750\/"},"modified":"2023-08-16T18:06:40","modified_gmt":"2023-08-16T18:06:40","slug":"301750","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/","title":{"rendered":"Reply To: Importing compressional test data for hyperelastic model fitting"},"content":{"rendered":"<p>&lt;p&gt;Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.&lt;\/p&gt;&lt;p&gt;<img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png\" width=\"440\" height=\"205\" \/><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692208777-mceclip1.png\" width=\"409\" height=\"193\" \/>&lt;\/p&gt;&lt;p&gt;&lt;span style=&#8221;font-size: 14pt;&#8221;&gt;When I manually fitted the negative stress-negative strain and input C10 C20 C30, LS-DYNA shows this error:&lt;\/span&gt;&lt;\/p&gt;&lt;p&gt;*** Error 40009 (SOL+9)&lt;br&gt;&nbsp; &nbsp; &nbsp;The time step size is zero.&lt;\/p&gt;&lt;p&gt;I have double checked that my timestep setup are correct. I don&#8217;t know how to resolve this issue.&lt;\/p&gt;&lt;p&gt;Is it normal that using an odgen\/hyperelastic\/rivlin model will make the simulation to be super slow?&lt;\/p&gt;&lt;p&gt;Another question is that if I use MAT_024_PIECEWISE_LINEAR_PLASTICITY, where the input stree-strain curve is effective stress versus effective plastic strain, which are supposed to be positive, how can I import my compression test result to it?&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-301750","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/\" \/>\n\t\t<meta property=\"og:image\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png\" \/>\n\t\t<meta property=\"og:image:secure_url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2023-08-16T18:06:40+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2023-08-16T18:06:40+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When\" \/>\n\t\t<meta name=\"twitter:image\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png\" \/>\n\t\t<script type=\"application\/ld+json\" class=\"aioseo-schema\">\n\t\t\t{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/301750\\\/#breadcrumblist\",\"itemListElement\":[{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/301750\\\/#listItem\",\"name\":\"Reply To: Importing compressional test data for hyperelastic model fitting\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/301750\\\/#listItem\",\"position\":2,\"name\":\"Reply To: Importing compressional test data for hyperelastic model fitting\",\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"name\":\"Home\"}}]},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#organization\",\"name\":\"Ansys Learning Forum\",\"description\":\"Ansys Innovation Space\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/301750\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/301750\\\/\",\"name\":\"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum\",\"description\":\"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When\",\"inLanguage\":\"en-US\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/301750\\\/#breadcrumblist\"},\"datePublished\":\"2023-08-16T18:06:40+00:00\",\"dateModified\":\"2023-08-16T18:06:40+00:00\"},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/\",\"name\":\"Ansys Learning Forum\",\"description\":\"Ansys Innovation Space\",\"inLanguage\":\"en-US\",\"publisher\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#organization\"}}]}\n\t\t<\/script>\n\t\t<!-- All in One SEO -->\n\n","aioseo_head_json":{"title":"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum","description":"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When","canonical_url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"BreadcrumbList","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/#breadcrumblist","itemListElement":[{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","position":1,"name":"Home","item":"https:\/\/innovationspace.ansys.com\/forum","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/#listItem","name":"Reply To: Importing compressional test data for hyperelastic model fitting"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/#listItem","position":2,"name":"Reply To: Importing compressional test data for hyperelastic model fitting","previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","name":"Home"}}]},{"@type":"Organization","@id":"https:\/\/innovationspace.ansys.com\/forum\/#organization","name":"Ansys Learning Forum","description":"Ansys Innovation Space","url":"https:\/\/innovationspace.ansys.com\/forum\/"},{"@type":"WebPage","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/#webpage","url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/","name":"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum","description":"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When","inLanguage":"en-US","isPartOf":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#website"},"breadcrumb":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/#breadcrumblist"},"datePublished":"2023-08-16T18:06:40+00:00","dateModified":"2023-08-16T18:06:40+00:00"},{"@type":"WebSite","@id":"https:\/\/innovationspace.ansys.com\/forum\/#website","url":"https:\/\/innovationspace.ansys.com\/forum\/","name":"Ansys Learning Forum","description":"Ansys Innovation Space","inLanguage":"en-US","publisher":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#organization"}}]},"og:locale":"en_US","og:site_name":"Ansys Learning Forum | Ansys Innovation Space","og:type":"article","og:title":"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum","og:description":"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When","og:url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/","og:image":"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png","og:image:secure_url":"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png","article:published_time":"2023-08-16T18:06:40+00:00","article:modified_time":"2023-08-16T18:06:40+00:00","twitter:card":"summary_large_image","twitter:title":"Reply To: Importing compressional test data for hyperelastic model fitting | Ansys Learning Forum","twitter:description":"Thanks for your reply. For the fitting issues, this is what I got using MAT_077_HYPERELASTIC with positive stress strain values (which is not correct because the experiment result is from compression tests). You can see in the second picture that the fitting went terrible when switch both stress and strain value to negative.When","twitter:image":"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/08\/16-08-2023-1692206683-mceclip0.png"},"aioseo_meta_data":{"post_id":"301750","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"content","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":true,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"limit_modified_date":false,"created":"2024-10-28 17:50:06","updated":"2026-09-09 00:31:58","ai":null,"breadcrumb_settings":null,"seo_analyzer_scan_date":null},"aioseo_breadcrumb":"<div class=\"aioseo-breadcrumbs\"><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/forum\" title=\"Home\">Home<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\tReply To: Importing compressional test data for hyperelastic model fitting\n\t\t<\/span><\/div>","aioseo_breadcrumb_json":[{"label":"Home","link":"https:\/\/innovationspace.ansys.com\/forum"},{"label":"Reply To: Importing compressional test data for hyperelastic model fitting","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/301750\/"}],"acf":[],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/301750","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/reply"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/301750\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=301750"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}