{"id":30720,"date":"2018-10-04T03:44:17","date_gmt":"2018-10-04T03:44:17","guid":{"rendered":"\/forum\/forums\/topic\/hyperelastic-multi-layered-tube-buckling-compression\/"},"modified":"2018-10-04T03:44:17","modified_gmt":"2018-10-04T03:44:17","slug":"hyperelastic-multi-layered-tube-buckling-compression","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/hyperelastic-multi-layered-tube-buckling-compression\/","title":{"rendered":"Hyperelastic multi-layered tube buckling\/compression"},"content":{"rendered":"<p>Hi All,<\/p>\n<p><\/p>\n<p>I am working on a project that involves a multilayered hyperelastic tubing that I would ultimately like to be able to place displacement compressions, twist it, bend it, etc. involving nonlinear frictional contact. I am currently treating these as Isotropic, but do have uniaxial, biaxial, and shear test data available for some Mooney-Rivlin parameter fittings&#8230; but figured I&#8217;d figure out Isotropic FIRST.<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p><strong>Geometry\/Materials:<\/strong><\/p>\n<p><\/p>\n<ul class=\"nova-e-list nova-e-list--size-m nova-e-list--type-unordered nova-e-list--spacing-auto\" style=\"list-style-position: outside; list-style-image: initial; margin: 0px 0px 1.42857em 1.2em; padding: 0px; color: #111111; font-family: Roboto, Arial, sans-serif; line-height: 1;\"><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3; margin-bottom: 0.5em;\">Inner tube: Silicone Rubber; Young&#8217;s Modulus: 250 psi (0.49 Poisson&#8217;s Ratio)<\/li>\n<p><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3;\">Second layer: Polyethylene terephthalate (PET) monofilament (treated as a 3D surface wrapped around in contact with the silicone); Young&#8217;s Modulus: 71,000 psi (0.49 Poisson&#8217;s Ratio)<\/li>\n<p><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3;\">Third Layer: Polyurethane 80A; Young&#8217;s Modulus: 500 psi (0.49 Poisson&#8217;s Ratio)<\/li>\n<p><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3;\">Fourth outer-most layer: Polyurethane 55D; Young&#8217;s Modulus: 2,500 psi (0.49 Poisson&#8217;s Ratio)<\/li>\n<p>\n<\/ul>\n<p><\/p>\n<p>The tubing below is 0.500&#8243; long.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/2ddaa98d-0a7d-4941-88e6-a96f0013fdfa\/c2751cbe-4798-4668-a5be-a96f0037edd7_geometry.jpg?width=690&amp;upscale=false\" alt=\"Geometry\"><\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p><strong>Contact:<\/strong><\/p>\n<p><\/p>\n<ul class=\"nova-e-list nova-e-list--size-m nova-e-list--type-unordered nova-e-list--spacing-auto\" style=\"list-style-position: outside; list-style-image: initial; margin: 0px 0px 1.42857em 1.2em; padding: 0px; color: #111111; font-family: Roboto, Arial, sans-serif; line-height: 1;\"><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3; margin-bottom: 0.5em;\">Silicone Rubber-&gt;PET: Frictional Contact with a coefficient of 0.1<\/li>\n<p><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3; margin-bottom: 0.5em;\">PET-&gt;PU80A: Frictional Contact with a coefficient of 0.1<\/li>\n<p><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3; margin-bottom: 0.5em;\">PU80A-&gt;PU55D: Bonded Contact<\/li>\n<p>\n<\/ul>\n<p><\/p>\n<p><strong style=\"color: #111111; font-family: Roboto, Arial, sans-serif;\">Mesh:<\/strong><\/p>\n<p><\/p>\n<ul><\/p>\n<li>I am currently utilizing hex dominant method. I&#8217;m not sure if Contact Match or Node Merge could come in handy here. Open for opinions regarding this kind of surface contact.<\/li>\n<p>\n<\/ul>\n<p><\/p>\n<p><strong>BCs:<\/strong><\/p>\n<p><\/p>\n<ul class=\"nova-e-list nova-e-list--size-m nova-e-list--type-unordered nova-e-list--spacing-auto\" style=\"list-style-position: outside; list-style-image: initial; margin: 0px 0px 1.42857em 1.2em; padding: 0px; color: #111111; font-family: Roboto, Arial, sans-serif; line-height: 1;\"><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3; margin-bottom: 0.5em;\">One end is fixed, and the other end faces have constraints in the x-z plane with a displacement of 0.1&#8243; in the negative y direction to compress towards the fixed end in hopes to induce a buckling shape.<\/li>\n<p><\/p>\n<li class=\"nova-e-list__item\" style=\"line-height: 1.3;\">There is also a pressure (fluid moving through the tubing) of 1 psi inside the silicone tubing.<\/li>\n<p>\n<\/ul>\n<p><\/p>\n<p><strong>Issues:<\/strong><\/p>\n<p><\/p>\n<ul><\/p>\n<li>As with most people, convergence. &#8220;Contact Status has Experienced an abrupt change&#8221;. Highly distorted elements.&nbsp;<\/li>\n<p><\/p>\n<li>I&#8217;ve even run my Eigenvalue Buckling to get my critical load factor that would induce my first buckling shape:<img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/2ddaa98d-0a7d-4941-88e6-a96f0013fdfa\/67069f18-2d2c-4f14-a718-a96f003b6d98_eigenmode1.jpg?width=690&amp;upscale=false\" alt=\"Eigenvalue Mode 1\"><\/li>\n<p>\n<\/ul>\n<p><\/p>\n<p>I took the Load Multiplier and multiplied that by my load applied to this tubing (1 lbf) to determine the critical buckling load, and then added ~20% increase to this value along with a perturbation in Nonlinear Structural to try to obtain some post-buckling behavior but had no success with this.<\/p>\n<p><\/p>\n<p>I&#8217;m a little lost with this, let alone how to even start including non-linear material modeling, so any help or thoughts is GREATLY appreciated!<\/p>\n<p><\/p>\n<p>Regards,<\/p>\n<p><\/p>\n<p>Zach<\/p>\n","protected":false},"template":"","class_list":["post-30720","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["2892"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0","0","0","0"],"_btv_view_count":["683"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["30720"],"_bbp_forum_id":["27791"],"_bbp_engagement":["88","240","897","159194"],"_bbp_voice_count":["4"],"_bbp_reply_count":["11"],"_bbp_last_reply_id":["65713"],"_bbp_last_active_id":["65713"],"_bbp_last_active_time":["2018-10-05 15:28:21"]},"test":"zjuv9021"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/30720","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\/30720\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=30720"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}