{"id":390249,"date":"2024-10-17T13:08:56","date_gmt":"2024-10-17T13:08:56","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/"},"modified":"2024-10-17T13:08:56","modified_gmt":"2024-10-17T13:08:56","slug":"390249","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/","title":{"rendered":"Reply To: Negative eroding contact energy in impact testing"},"content":{"rendered":"<p>&lt;p&gt;Hi,&lt;\/p&gt;&lt;p&gt;Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.&lt;\/p&gt;&lt;p&gt;I&#8217;ve also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don&#8217;t change my timestep at all, but the higher I set them, the more unstable the model becomes (ie total energy increases by &gt;4%, negative contact energy, etc). The only times I find that there&#8217;s no negative eroded internal energy is when the material behaves &#8220;softly&#8221;, deflecting outwards when compression is experienced. Perhaps overstiff behaviour is present in my model? The element failures on the projectile can be seen below, in blue.&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.png\" \/>&lt;\/p&gt;&lt;p&gt;They appear in &#8220;Spots&#8221; away from the impact location, seemingly randomly. I have a feeling that the material is deleting them due to negative volume, because they&#8217;re not failing normally. The wood material manual does say that when the elements perpendicular to the grain reach failure criteria, they don&#8217;t fail unless they reach negative volume. Just in case, is there anything off about my material inputs for MAT 143?&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729170239-mceclip5.png\" \/>&lt;\/p&gt;&lt;p&gt;I typically have IFAIL off, I just had it on in that screenshot for debugging, and it didn&#8217;t eliminate the negative internal energies. I also set A3 in the negative Z axis because that&#8217;s the direction my projectile is travelling, but I don&#8217;t think that made a difference when I changed it either.&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-390249","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=\"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I&#039;ve also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don&#039;t\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/\" \/>\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: Negative eroding contact energy in impact testing | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I&#039;ve also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don&#039;t\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/\" \/>\n\t\t<meta property=\"og:image\" content=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.png\" \/>\n\t\t<meta property=\"og:image:secure_url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.png\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2024-10-17T13:08:56+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2024-10-17T13:08:56+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Reply To: Negative eroding contact energy in impact testing | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I&#039;ve also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don&#039;t\" \/>\n\t\t<meta name=\"twitter:image\" content=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.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\\\/390249\\\/#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\\\/390249\\\/#listItem\",\"name\":\"Reply To: Negative eroding contact energy in impact testing\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/390249\\\/#listItem\",\"position\":2,\"name\":\"Reply To: Negative eroding contact energy in impact testing\",\"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\\\/390249\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/390249\\\/\",\"name\":\"Reply To: Negative eroding contact energy in impact testing | Ansys Learning Forum\",\"description\":\"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I've also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don't\",\"inLanguage\":\"en-US\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/reply\\\/390249\\\/#breadcrumblist\"},\"datePublished\":\"2024-10-17T13:08:56+00:00\",\"dateModified\":\"2024-10-17T13:08:56+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: Negative eroding contact energy in impact testing | Ansys Learning Forum","description":"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I've also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don't","canonical_url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"BreadcrumbList","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/#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\/390249\/#listItem","name":"Reply To: Negative eroding contact energy in impact testing"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/#listItem","position":2,"name":"Reply To: Negative eroding contact energy in impact testing","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\/390249\/#webpage","url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/","name":"Reply To: Negative eroding contact energy in impact testing | Ansys Learning Forum","description":"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I've also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don't","inLanguage":"en-US","isPartOf":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#website"},"breadcrumb":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/#breadcrumblist"},"datePublished":"2024-10-17T13:08:56+00:00","dateModified":"2024-10-17T13:08:56+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: Negative eroding contact energy in impact testing | Ansys Learning Forum","og:description":"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I've also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don't","og:url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/","og:image":"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.png","og:image:secure_url":"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.png","article:published_time":"2024-10-17T13:08:56+00:00","article:modified_time":"2024-10-17T13:08:56+00:00","twitter:card":"summary_large_image","twitter:title":"Reply To: Negative eroding contact energy in impact testing | Ansys Learning Forum","twitter:description":"Hi,Sorry, I meant the RCFORC results for SURFA and SURFB were slightly different at some times when I changed the SLSFAC factor. Additionally, shortly after the seemingly positive eroded internal energy, it dips and becomes negative again.I've also since then tried varying combinations of SLSFAC, TSSFAC, SFSA and SFSB. It seems SFSA and SFSB don't","twitter:image":"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/10\/17-10-2024-1729169874-mceclip4.png"},"aioseo_meta_data":{"post_id":"390249","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 16:22:48","updated":"2024-10-28 16:22:48","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: Negative eroding contact energy in impact testing\n\t\t<\/span><\/div>","aioseo_breadcrumb_json":[{"label":"Home","link":"https:\/\/innovationspace.ansys.com\/forum"},{"label":"Reply To: Negative eroding contact energy in impact testing","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/390249\/"}],"acf":[],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/replies\/390249","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\/390249\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=390249"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}