{"id":30709,"date":"2018-10-03T15:51:20","date_gmt":"2018-10-03T15:51:20","guid":{"rendered":"\/forum\/forums\/topic\/how-to-use-linear-periodic-symmetry\/"},"modified":"2018-10-03T15:51:20","modified_gmt":"2018-10-03T15:51:20","slug":"how-to-use-linear-periodic-symmetry","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-use-linear-periodic-symmetry\/","title":{"rendered":"How to use Linear Periodic Symmetry"},"content":{"rendered":"

Hello,<\/p>\n

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I am trying to set a symmetry on a model which has a repetitive structure so I am trying to use a symmetry region of a linear periodic type.<\/p>\n

<\/p>\n

My model is a sandwich panel with a kagome lattice type core. The core consists of beam bodies and the facesheets of surface bodies:<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

 <\/p>\n

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The original sandwich is after hiding the top face can be seen here:<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

I want to cut the panel in half and model the 1\/2 of it by applying a symmetry boundary condition, but since the core is not normal symmetrical but has a repetitive pattern I am trying to use linear periodeic symmetry region.<\/p>\n

<\/p>\n

After cutting accordingly the repetitive half that remains is the following:<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

I set the low boundary in the following edges of the facesheets:<\/p>\n

<\/p>\n

\"\"<\/p>\n

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and the high boundary in the according opposite edges of the facesheets :<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

I set the coordinate system at the high boundary edges:<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

\"\"<\/p>\n

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and set the linear shift value as the distance of these edges: 36,83mm in the Y periodicity direction.<\/p>\n

<\/p>\n

The model gets meshed but it doesn’t run, I get different pivot warnings each time and have to limit a node every time with a remote displacement bc.<\/p>\n

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After setting the grapcical extension in ΔY : \"\"<\/p>\n

<\/p>\n

 <\/p>\n

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I hit show mesh and I get the following :<\/p>\n

<\/p>\n

\"\"<\/p>\n

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(again the upper facesheet is hided).<\/p>\n

<\/p>\n

So the linear periodic symmetry is not applied, or at least is not shown to be applied. A normal symmetry is showed and the core is not as it should be.<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

The surface bodies of the facesheets and the beam bodies of the core share topology from spaceclaim. The setup is a three point bending test:<\/p>\n

<\/p>\n

\"\"<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

How can I correctly set the symmetry in this model? It is also of interest to model th 1\/4th of the panel by applying another linear periodic symmetry bc along the X direction.<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

Also does this idea of linear periodic symmetry make sense for two repetitions, or is the linear periodic feature only for infinite repetitions?<\/p>\n

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 <\/p>\n

<\/p>\n

I want to use the symmetry in order to get necessary constraints in the static structural analysis of the sandwich panel.<\/p>\n

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Can you help me?<\/p>\n

<\/p>\n

 <\/p>\n

<\/p>\n

With Gratitude,<\/p>\n

<\/p>\n

Achilleas Milios<\/p>\n

<\/p>\n

 <\/p>\n","protected":false},"template":"","class_list":["post-30709","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["2881"],"_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":["4080"],"_bbp_subscription":["236903","284237"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["30709"],"_bbp_forum_id":["27791"],"_bbp_engagement":["88","240","158421","178272","284237"],"_bbp_voice_count":["5"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["284304"],"_bbp_last_active_id":["284304"],"_bbp_last_active_time":["2023-05-16 18:43:37"]},"test":"achilleasmil"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/30709","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\/30709\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=30709"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}