Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

Humberto · 2015-09-18 22:49:52

[SOLVED] please check on the bottom of the thread for the working command.comm file.

Hello I am doing a simple test, to learn the process of using Code_Aster for the structural analysis of buildings with beams and walls and some loadcases.

The case fails telling me that the stiffness matrix is singular, I do not understand why as I set the fix points rigid in both x,y,z translations and also for the 3 rotations.

I am thinking that even when I built the model from the fixed nodes, and then did the beams and then did the planes, to combine all in a compound, maybe the plates are not connected to the beams. I have no idea.

I hope you can help me get this model working and hopefully it will help others too.

Command.comm:
Please Download the one on the bottom of the thread.

Mesh(.mmed):
https://drive.google.com/file/d/0B3df_K … sp=sharing

Study(.hdf):
https://drive.google.com/file/d/0B3df_K … sp=sharing

mLRTpOc.png?1

Last edited by Humberto (2015-09-28 17:31:19)

Attachments:
view.png, Size: 43.63 KiB, Downloads: 359

jeanpierreaubry · 2015-09-19 08:47:13

hello

first of all

maybe the plates are not connected to the beams

that is it
you have an awful lot of double nodes, probably coming from the way yo meshed lines and surfaces
to see them and delete them , in Salome Mesh module
Modification > Transformation > Merges nodes, Manual ticked, pic attached
correct that first
afterward there are some incongruities in the .comm file that i let you discover

jean pierre aubry

Last edited by jeanpierreaubry (2015-09-19 08:50:24)

Attachments:
humberto.png, Size: 186.2 KiB, Downloads: 388

Humberto · 2015-09-21 23:37:21

Thanks Jean, I did fix the mesh and discovered the incongruity, One of my step functions was not defined in inst = 0 because I forgot Prol Droite, and Gauche, I also created more groups for my walls as to be able to easily define the local system with VECTEUR,

But For some reason my Sipo elements and my stress components in the plates, all have a unique value in all the field, I just can't see the right stresses on the walls, but the displacements look ok.

Please point me in the right direction, to be able to see the stresses in the plates (DKT).

I did follow your book but kept getting the same unique value fields problem.

Regards.

Humberto .

I just Updated the files on the links above to my working and latest model.

jeanpierreaubry · 2015-09-22 07:16:43

there is another incongruity, regarding the stepping for the solution commented in the attached file
some of the INST do not mean much, they have the same loading!

But For some reason my Sipo elements and my stress components in the plates, all have a unique value in all the field.

i do not understand i can see all ok in Gmsh

Please point me in the right direction, to be able to see the stresses in the plates (DKT).

this is on page 100 and in the attached file

Last edited by jeanpierreaubry (2015-09-22 07:17:22)

Attachments:
Command.comm, Size: 6.07 KiB, Downloads: 374

Humberto · 2015-09-24 23:04:31

Thanks Jean, Thank you so much for your comments.

Your command.comm works, I can now see the Von Misses Stress on the plates, I tweaked the command file a little and changed the SIPO field to SIEF_ELNO to have the forces on the beams, I still can not read those on paravis.

I will keep trying and once I get the the forces correctly displayed and printed into a table as you suggested, I will post the final command file so anyone interested in the process of calculation of such a structure can study it.

I am glad I tried this little structure, because I have learnt a lot in the process. I hope this is also a good tutorial to other engineers out there.

Humberto.

Humberto · 2015-09-27 21:54:41

Jean:
Thank you very much for your help in the process of solving this Auto-tutorial.

Now the model works perfectly. I am attaching the Command.com file so that anyone can download it and learn from it.

How do I mark this thread as [Solved] ?

Last edited by Humberto (2015-09-27 21:59:55)

Attachments:
Command.comm, Size: 6.82 KiB, Downloads: 399

#1 2015-09-18 22:49:52

Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

#2 2015-09-19 08:47:13

Re: Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

#3 2015-09-21 23:37:21

Re: Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

#4 2015-09-22 07:16:43

Re: Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

#5 2015-09-24 23:04:31

Re: Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

#6 2015-09-27 21:54:41

Re: Simple structure with Beam (POU_DT)and diafragm plates (DKT) analysis.

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