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#1 2020-06-08 09:41:34

saikirred
Member
Registered: 2020-06-08
Posts: 3

global Stress results visualization for shell DKT element is wired

Hello, I am new to code Aster and working on salome-meca 2019 version, I have created a 2D beam with shell element DKT, fixed at one end and a load of Fz= -1000N as been applied at other end and displacement result obtained are accurate when compared to the Abaqus values. but the global stress visualization, I have seen wired stress distribution, that is on each element there is a compression and tension acting on it, unable to understand why?.

and also I see a stress value at S_z=0 at along zz-direction? which is a bit uneven for me to understand now? max stress obtained is S_x=170Mpa and S_y= 51Mpa. so can anyone please let me know why is this behavior of stresses are seen?


So, did I make any mistake in modeling or is it due to the element? and also I am unable to visualize the elementary stress results for shell elements, only able to see the max and min point? please find the attachment below, attached a displacement plot, global stress, and elementary stress.


Thanks
Sai

Last edited by saikirred (2020-06-09 17:43:59)


Attachments:
shellelementsplots.zip, Size: 200.74 KiB, Downloads: 17

Thanks
Sai

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#2 2020-06-26 19:44:36

Vamsi
Member
Registered: 2018-07-03
Posts: 3

Re: global Stress results visualization for shell DKT element is wired

Please use operator "POST_CHAMP" for specific post processing of stresses from Shell Elements.

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#3 2020-06-26 21:40:01

tpa
Member
From: Denmark
Registered: 2009-04-14
Posts: 39

Re: global Stress results visualization for shell DKT element is wired

In human words: For plate/shell elements CALC_ELEM calculates SIGM_ELNO stresses in layers: top (SUP), middle (MOY) and bottom (INF). You have to extract the layer of interest to a separate result by using the EXTR_COQUE function of POST_CHAMP command, and then also remember this additional result in the IMPR_RESU command if you want to visualize in ParaVIS.

The thread "[SOLVED] Plotting stresses from DKT elements" has a .comm file giving an example.

I think that these extra steps are because ParaVIS is not optimized to understand the complex information provided by relatively simple element types such as the shell plate and beam elements. When it comes to that the old POST_PRO was bit better integrated with the code_aster data structures.

Last edited by tpa (2020-06-26 21:48:58)

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#4 2020-06-29 19:51:23

saikirred
Member
Registered: 2020-06-08
Posts: 3

Re: global Stress results visualization for shell DKT element is wired

Thanks for your suggestions, now the model is working, and stresses results are plotted accordingly when used with operator Post_Champ. Thank you all for your comments.


Thanks
Sai

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