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#1 Re: Code_Aster usage » Difference between ENCASTRE and DX=0, DY=0, DZ=0, DRX=0, DRY=0, DRZ=0 » 2022-02-04 13:33:41

it seems you are trying to impose a boundary condition on DOFs that don't exist in your modelization. Can you share your model (comm and mesh files)?


#2 Re: Code_Aster usage » Coredump error for v. 14.4, docker image » 2022-02-01 17:28:18

Hi KnutVedeld,

I was able to run (Code_Aster 14.4.0) your case with the following content of the .export file:

P actions make_etude
P detr_rep_trav oui
P mem_aster 100
P mode interactif
P mpi_nbcpu 1
P mpi_nbnoeud 1
P ncpus 1
P version stable
A args -max_base 100000
A memjeveux 150
A tpmax 36000
F comm SimplePlate.comm D  1
F libr SimplePlate.astr D  3
F mess SimplePlate.mess R  6

You can try to merge it step by step with your .export file to see what is causing your problem. Hope this helps.

#3 Re: Code_Aster usage » Contact with SIMO_MIEHE » 2022-01-27 11:26:14

Hi rupole1185,
How did the analysis with increased tangent modulus go?
I have not looked at the files you sent yet.

The fact your analysis converges with fully elastic material is good news I think. I would explore the material properties and make it a displacement control problem with small enforced displacement. If you will have some results to look at then maybe you could eyeball potential issues with the mesh being deformed etc.

#4 Re: Code_Aster usage » Contact with SIMO_MIEHE » 2022-01-26 19:56:47

It depends a bit on the results you are after but in general, you could use the shell elements to represent a stiffness of a waved gasket. But I cannot give you a lot of advice on what modelization to use. I have some experience with metal forming simulations and usage of shells, but not in Code Aster.
Perhaps you could try building a simpler mesh: two solid blocks with a waved strip of "gasket" in-between to check various modelizations.

Do you use an automatic time step decrease method if non-convergence occurs: DEFI_LIST_INST, METHODE=AUTO?
Can you share your mess file?

#5 Re: Code_Aster usage » Contact with SIMO_MIEHE » 2022-01-26 17:23:38

Is it a displacement or force-controlled problem?
I don't have experience with the elements you are using there for the gasket, but if the elastic model converges then I would look closer at the material properties. In particular the definition of the tangent modulus. Have you tried to increase the tangent modulus for the elastoplastic material?

#6 Re: Code_Aster usage » Contact with SIMO_MIEHE » 2022-01-26 14:17:44

Hi rupole1185,

it could be couple of things, as you probably know.
1. I would try to change the material to linear elastic formulation and check if the analysis converges.
2. I would also try to ramp the "squeezing" at a lower rate.
3. How many elements does the gasket have through thickness? Can you make a snapshot showing the contact region of the gasket/housings? Try changing the contact do bonded ad see if it converges.

By checking 1,2, and finally three you might get a better idea about where the problem is.