


{"id":356044,"date":"2024-03-08T07:39:56","date_gmt":"2024-03-08T07:39:56","guid":{"rendered":"\/forum\/forums\/topic\/nonlinear-buckling-analysis-2\/"},"modified":"2024-03-08T07:39:56","modified_gmt":"2024-03-08T07:39:56","slug":"nonlinear-buckling-analysis-2","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/nonlinear-buckling-analysis-2\/","title":{"rendered":"nonlinear buckling analysis"},"content":{"rendered":"<p>Hello there,<br \/>Sorry for the long explanation in advance.<br \/>If I can send my ansys file to one of the ansys experts, it would be better to check my work if that is possible, and I&#8217;m also going to attach some screenshots of my work.<br \/>&nbsp;<br \/>I&#8217;m doing nonlinear buckling analysis, and I also want to do the ARC length method to predict post-buckling behavior using the ANSYS 2023 student license for conical tanks I want to use ASYS results to develop a code to predict the minimum wall thickness to avoid buckling and failure.&nbsp;<br \/>I used the design modeler to draw my geometry with 3 different surfaces; each one has a different thickness, and those thicknesses are like this from top to bottom.&nbsp;<br \/>6.4 for the upper part, 8 for the mid part, and 10 for the lower part, and I want to assign steel material for the linear case and bilinear isotropic hardening for the nonlinear case.&nbsp;<br \/>i used two connections to connect those surfaces to each other the bonded type and for mesh i used element size 400 mm also i used mesh size option and i insert node merge option twice to merge all nodes together also i used mesh numbering to make sure do not exceed the limitation for student license which is i think around 3500 nodes in total and i put value of 10 to consider the geometry imperfication and for linear step i turned of large deformation option after that i started to insert my boundray condition which is displacement on the top x=z=0 and y free and i also insert same displacement for bottom edge but in this case i wanna x=y=z=0 and i also have hedrostatic pressure from inside with value for fluid density is 1400 kg\/ m^3 and x=z=0 and for y=9.81 m\/s^2 at surface y= 9m for surface location and also the standard gravity after that i insert the total deformation and &nbsp;equivalent stress for static structure and for eigenvalue buckling i insert the total deformation &nbsp;and i did same steps for nonlinear with turn on large deformation and turn off the line search and stabilization and i assign the bilinear material for this step to the geometry &nbsp;<br \/>I have some questions: 1. When I&#8217;m defining the materials, specifically the bilinear case, there is something wired in the stress-strain chart; it should be more than just an inclined line. By the way, I&#8217;m going to post photos to make it clear.<br \/>2. For my results, it doesn&#8217;t make sense, especially for convergence,deformation and stress.&nbsp;<br \/>3- For the arc length method, as I saw from the previous discussion here, it&#8217;s not applicable for this version, and I already watched the video for homework (2) when they explained how we can do the arc length. I tried this way, but I think they used line bodies, and they ended up with code. They wrote it in the command option, but I&#8217;m not sure how I can do it for my model.&nbsp;<br \/>Thanks in advance for everything. and I&#8217;m looking forward to hearing from you.<br \/>Best regards<br \/>Jamil Atileh&nbsp;<br \/>&nbsp;<br \/>&nbsp;1- the chart should be like this&nbsp;<br \/>&nbsp;<img loading=\"lazy\" decoding=\"async\" title=\"stress-strain chart \" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709879918-Screenshot 2024-03-08 013813.png\" alt=\"bilinear isotropic hardening\" width=\"255\" height=\"186\"><\/p>\n<p>but my chart like this&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709880120-Screenshot 2024-03-08 013629.png\" alt=\"\" width=\"264\" height=\"153\"><\/p>\n<p>2- My results for linear buckling&nbsp;<\/p>\n<p>eigenvalue total deformation&nbsp;&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881887-Screenshot 2024-03-08 021058.png\" alt=\"\" width=\"373\" height=\"221\"><\/p>\n<p>static analysis total deformation and stress (von mises)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881964-Screenshot 2024-03-08 021217.png\" alt=\"\" width=\"322\" height=\"192\"><\/p>\n<p>stress<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709880549-Screenshot 2024-03-08 014849.png\" alt=\"\" width=\"389\" height=\"232\"><\/p>\n<p>directional deformation<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709880639-Screenshot 2024-03-08 015019.png\" alt=\"\" width=\"310\" height=\"185\"><\/p>\n<p>mesh<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709880792-Screenshot 2024-03-08 015249.png\" alt=\"\" width=\"355\" height=\"212\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881559-Screenshot 2024-03-08 020526.png\" alt=\"\" width=\"390\" height=\"234\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881634-Screenshot 2024-03-08 020658.png\" alt=\"\" width=\"393\" height=\"235\"><\/p>\n<p>boundray conditions<\/p>\n<p>standard earth gravity<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709880909-Screenshot 2024-03-08 015449.png\" alt=\"\" width=\"245\" height=\"146\"><\/p>\n<p>hedrostatic pressure<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881064-Screenshot 2024-03-08 015725.png\" alt=\"\" width=\"320\" height=\"190\"><\/p>\n<p>displacement at top and bottom<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881150-Screenshot 2024-03-08 015847.png\" alt=\"\" width=\"344\" height=\"205\"><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881202-Screenshot 2024-03-08 015946.png\" alt=\"\" width=\"319\" height=\"191\"><\/p>\n<p>connections<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881373-Screenshot 2024-03-08 020222.png\" alt=\"\" width=\"347\" height=\"206\"><\/p>\n<p>geometry&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709881473-Screenshot 2024-03-08 020354.png\" alt=\"\" width=\"257\" height=\"153\"><\/p>\n<p>3-for nonlinear analysis<\/p>\n<p>geometry&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709882487-Screenshot 2024-03-08 022050.png\" alt=\"\" width=\"289\" height=\"172\"><\/p>\n<p>anaylsis settings<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709882571-Screenshot 2024-03-08 022216.png\" alt=\"\" width=\"300\" height=\"179\"><\/p>\n<p>total deformation<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709882687-Screenshot 2024-03-08 022341.png\" alt=\"\" width=\"260\" height=\"154\"><\/p>\n<p>stress<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709882748-Screenshot 2024-03-08 022526.png\" alt=\"\" width=\"305\" height=\"181\"><\/p>\n<p>convergence<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709882809-Screenshot 2024-03-08 022613.png\" alt=\"\" width=\"284\" height=\"169\"><\/p>\n<p>messages&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709882904-Screenshot 2024-03-08 022724.png\" alt=\"\" width=\"346\" height=\"205\"><\/p>\n<p>geometry imperfecation<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/03\/08-03-2024-1709883024-Screenshot 2024-03-08 022919.png\" alt=\"\" width=\"351\" height=\"118\">&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-356044","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["38540","88"],"_bbp_author_ip":["23.52.43.10"]," _bbp_last_reply_id":["0"]," 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17:46:58"]},"test":"jatilehuwo-ca"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/356044","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\/356044\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=356044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}