{"id":303035,"date":"2023-08-24T11:50:13","date_gmt":"2023-08-24T11:50:13","guid":{"rendered":"\/forum\/?post_type=topic&p=303035"},"modified":"2023-08-24T12:23:12","modified_gmt":"2023-08-24T12:23:12","slug":"validation-of-non-linear-compressive-behaviour-of-resin-printed-structures","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/validation-of-non-linear-compressive-behaviour-of-resin-printed-structures\/","title":{"rendered":"Validation of non-linear compressive behaviour of resin-printed structures"},"content":{"rendered":"

Hello everybody,<\/p>\n

I am trying to simulate a compression test (static analysis) of a porous structure to validate results over experimental data. Samples are 3D printed through SLA (Formlabs 3B, Flexible 80A resin).<\/p>\n

First, I experimentally characterised the material properties in compression, then obtained a material model in Workbench (Ogden 1st Order). <\/p>\n

My geometry is a porous structure with a spherical unit cell (full structure, first picture), the simulation is performed using symmetries in the x- and z- directions (second picture).<\/p>\n

\"\"<\/a>\"\"<\/a><\/p>\n

BCs. Upper surface: uY ≠ 0; uX = uZ = 0; lower surface: fixed support (I tried just uY = 0 but had convergence issues).<\/p>\n

The engineering stresses and strains are obtained from FE results (stress = reaction force \/ initial cross section; strain = displacement \/ initial length) and compared to the ones obtained from the testing machine. Here is the simluation results compared to the experimental ones.<\/p>\n

\"\"<\/a><\/p>\n

Two questions arise:<\/p>\n

1) The first regions overlap with good agreement, until buckling of the structure occurs – which is not detected in the simulation. Is there anything missing in the model? Maybe the printed structure has many imperfections due to the printing process so buckling occurs much before than if considering the designed (then “perfect”) one? (I ran a different simulation on the same structure without symmetries, obtaining a buckled curve, maybe confirming my thought?)<\/p>\n

2) Depending on the used geometry (the picture above shows 1\/14 symmetric region) simulations don’t always converge for high strains, due to highly distorted elements. I know this is a very frequent matter with hyperelastic materials and I have tried to solve by reading\/watching videos: I tried (local) remeshing, NLAD, etc but apparently I cannot overcome this problem right now.<\/p>\n

Here is the link to the archived project https:\/\/drive.google.com\/file\/d\/1JHpWhteu_Wn1ZezxKyFEAj8fhTru21VL\/view?usp=drive_link.<\/p>\n

Thanks in advance, any suggestions would be highly appreciated \ud83d\ude42<\/p>\n

 <\/p>\n","protected":false},"template":"","class_list":["post-303035","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":["96.7.218.215"],"_bbp_subscription":["23572","99","50680"],"_btv_view_count":["325"],"_edit_lock":["1692879800:227084"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["303035"],"_bbp_forum_id":["27791"],"_bbp_engagement":["99","23572","50680"],"_bbp_voice_count":["3"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["304400"],"_bbp_last_active_id":["304400"],"_bbp_last_active_time":["2023-08-31 15:29:46"]},"test":"pasquale-posabella-doktpw-edu-pl"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/303035","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\/303035\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=303035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}