


{"id":318313,"date":"2023-11-18T19:50:17","date_gmt":"2023-11-18T19:50:17","guid":{"rendered":"\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/"},"modified":"2023-11-23T17:59:57","modified_gmt":"2023-11-23T17:59:57","slug":"gravity-causing-rigid-body-motion","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/","title":{"rendered":"Gravity causing rigid body motion?"},"content":{"rendered":"<p>Hi,<\/p>\n<p>I&#8217;m having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.<\/p>\n<p>I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 &#8211; 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure loads on the bridge deck elements but the global gravity load seems to always cause it to fail.<\/p>\n<p>Am I missing something about how ACEL works? I&#8217;ve used DK to apply my boundary conditions. I&#8217;m not sure how the solution can solve with applied loads but not for gravity since surely any issues with my boundary conditions would apply to both cases.&nbsp;<\/p>\n<p>Any advice appreciated thanks.<\/p>\n<p><a class=\"wp-colorbox-image cboxElement\" href=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png\"><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png\"><\/a><\/p>\n","protected":false},"template":"","class_list":["post-318313","topic","type-topic","status-closed","hentry","topic-tag-boundary-conditions","topic-tag-constrain-problem-2","topic-tag-gravity-acceleration-2","topic-tag-static-strucural-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hi,I&#039;m having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/\" \/>\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=\"Gravity causing rigid body motion? | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hi,I&#039;m having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/\" \/>\n\t\t<meta property=\"og:image\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png\" \/>\n\t\t<meta property=\"og:image:secure_url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2023-11-18T19:50:17+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2023-11-23T17:59:57+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Gravity causing rigid body motion? | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"Hi,I&#039;m having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure\" \/>\n\t\t<meta name=\"twitter:image\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-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\\\/topic\\\/gravity-causing-rigid-body-motion\\\/#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\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"position\":2,\"name\":\"Topics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/boundary-conditions\\\/#listItem\",\"name\":\"boundary-conditions\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"name\":\"Home\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/boundary-conditions\\\/#listItem\",\"position\":3,\"name\":\"boundary-conditions\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/boundary-conditions\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/gravity-causing-rigid-body-motion\\\/#listItem\",\"name\":\"Gravity causing rigid body motion?\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/gravity-causing-rigid-body-motion\\\/#listItem\",\"position\":4,\"name\":\"Gravity causing rigid body motion?\",\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/boundary-conditions\\\/#listItem\",\"name\":\"boundary-conditions\"}}]},{\"@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\\\/topic\\\/gravity-causing-rigid-body-motion\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/gravity-causing-rigid-body-motion\\\/\",\"name\":\"Gravity causing rigid body motion? | Ansys Learning Forum\",\"description\":\"Hi,I'm having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\\\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\\\/mm3, E in N\\\/mm2). 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The model seems to solve correctly when I apply pressure","canonical_url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"BreadcrumbList","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/#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\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","position":2,"name":"Topics","item":"https:\/\/innovationspace.ansys.com\/forum\/topics\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/boundary-conditions\/#listItem","name":"boundary-conditions"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","name":"Home"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/boundary-conditions\/#listItem","position":3,"name":"boundary-conditions","item":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/boundary-conditions\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/#listItem","name":"Gravity causing rigid body motion?"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/#listItem","position":4,"name":"Gravity causing rigid body motion?","previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/boundary-conditions\/#listItem","name":"boundary-conditions"}}]},{"@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\/topic\/gravity-causing-rigid-body-motion\/#webpage","url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/","name":"Gravity causing rigid body motion? | Ansys Learning Forum","description":"Hi,I'm having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure","inLanguage":"en-US","isPartOf":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#website"},"breadcrumb":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/#breadcrumblist"},"datePublished":"2023-11-18T19:50:17+00:00","dateModified":"2023-11-23T17:59:57+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":"Gravity causing rigid body motion? | Ansys Learning Forum","og:description":"Hi,I'm having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure","og:url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/","og:image":"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png","og:image:secure_url":"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png","article:published_time":"2023-11-18T19:50:17+00:00","article:modified_time":"2023-11-23T17:59:57+00:00","twitter:card":"summary_large_image","twitter:title":"Gravity causing rigid body motion? | Ansys Learning Forum","twitter:description":"Hi,I'm having an issue where the global acceleration from ACEL seems to be causing rigid body motion in my bridge model.I have set gravity to -9806.5 mm\/s2 and have my densities and other material properties in matching units (~0.002 - 0.008 g\/mm3, E in N\/mm2). The model seems to solve correctly when I apply pressure","twitter:image":"https:\/\/innovationspace.ansys.com\/forum\/forum\/wp-content\/uploads\/sites\/2\/2023\/11\/18-11-2023-1700336937-mceclip0.png"},"aioseo_meta_data":{"post_id":"318313","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 17:32:59","updated":"2024-10-28 17:32:59","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\t<a href=\"https:\/\/innovationspace.ansys.com\/forum\/topics\/\" title=\"Topics\">Topics<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/boundary-conditions\/\" title=\"boundary-conditions\">boundary-conditions<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\tGravity causing rigid body motion?\n\t\t<\/span><\/div>","aioseo_breadcrumb_json":[{"label":"Home","link":"https:\/\/innovationspace.ansys.com\/forum"},{"label":"Topics","link":"https:\/\/innovationspace.ansys.com\/forum\/topics\/"},{"label":"boundary-conditions","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic-tag\/boundary-conditions\/"},{"label":"Gravity causing rigid body motion?","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/gravity-causing-rigid-body-motion\/"}],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["302481","88"],"_bbp_author_ip":["23.52.43.81"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["540"],"_edit_lock":["1700424147:244411"],"_bbp_status":["publish"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["318313"],"_bbp_forum_id":["27791"],"_bbp_engagement":["88","302481"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["318828"],"_bbp_last_active_id":["318828"],"_bbp_last_active_time":["2023-11-21 13:50:12"]},"test":"daniel-woods-6student-manchester-ac-uk"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/318313","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\/318313\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=318313"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}