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#1 Code_Aster usage » Combining multiple results into single *.rmed » 2022-12-30 19:59:51

EnKiNekiDela
Replies: 3

Greeting friends,

At post-processing when combining multiple sequential results into single rmed file visualization at post-processing gives "Deformed representation" just for first result eg DEPL_1 (only DX, DY...possible no "Magnitude" like at single result case) and after switching for  DEPL_2 this tab "vanishes" in a way no visualizations are possible for next result eg. DEPL_2 (see attached image). And
Sequential times are not overlapping, results are timely not overlapping.
In case NOM_CHAM_MED is not specified, Stage returns an error due to several existing CHAMs for one time step.

Here is art of that code:
IMPR_RESU(RESU=(_F(CRITERE='ABSOLU',
                   LIST_INST=tim21_out,
                   NOM_CHAM=('ACCE', 'VITE', 'DEPL'),
                   NOM_CHAM_MED=('resnonl2ACCE_1', 'resnonl2VITE_1', 'resnonl2DEPL_1'),
                   PRECISION=prec_parav_out,
                   RESULTAT=resnonl21),
                _F(CRITERE='ABSOLU',
                   LIST_INST=tim22_out,
                   NOM_CHAM=('ACCE', 'VITE', 'DEPL'),
                   NOM_CHAM_MED=('resnonl2ACCE_2', 'resnonl2VITE_2', 'resnonl2DEPL_2'),
                   PRECISION=prec_parav_out,
                   RESULTAT=resnonl22),
                _F(CRITERE='ABSOLU',
                   LIST_INST=tim23_out,
                   NOM_CHAM=('ACCE', 'VITE', 'DEPL'),
                   NOM_CHAM_MED=('resnonl2ACCE_3', 'resnonl2VITE_3', 'resnonl2DEPL_3'),
                   PRECISION=prec_parav_out,
                   RESULTAT=resnonl23)),
          UNITE=21)

Any ideas would be appreciated. Of course  I can do a "workaround" with paravis importing and animating partial results in sequence, but having this out of the box option would be very beneficial.

Thank you for your help and kind regards.

#2 Re: Code_Aster usage » Unknown operator: LIAISON_SOLIDE_SPH » 2022-12-30 18:37:30

Hello, thank you for your answer.

Would you be o kind and just share information if they are pat of some special non-public libraries?

Thank you and best regards.

#3 Code_Aster usage » Unknown operator: LIAISON_SOLIDE_SPH » 2022-12-10 12:42:48

EnKiNekiDela
Replies: 5

Dear colleagues,

This is a strange one!
During my endeavors to speed up calculations at friction between rigid bodies I tried also with the help of OpenAI GPT.

The task is as follows:
Simulate the time-history response of a spherical friction joint with a specified radius between only two nodes in CODE_ASTER.

Proposed code by OpenAI GPT for this task is:

! Define the two bodies involved in the friction joint
DEFI_GROUP(reuse=BODY_1,
           MAILLAGE=mesh_body_1,
           CREA_GROUP_MA=_F(
               OPERATION='ASSOCIE',
               TYPE_GROUP_MA='MAILLE'
           ))

DEFI_GROUP(reuse=BODY_2,
           MAILLAGE=mesh_body_2,
           CREA_GROUP_MA=_F(
               OPERATION='ASSOCIE',
               TYPE_GROUP_MA='MAILLE'
           ))

! Define the contact between the two bodies
LIAISON_SOLIDE_SPH(reuse=CONTACT,
                   TYPE_LIAISON='FROTTEMENT',
                   GROUP_MA_1=BODY_1,
                   GROUP_MA_2=BODY_2,
                   NOEUD_1=node_1,
                   NOEUD_2=node_2,
                   RAYON=joint_radius,
                   COEF_FROTTEMENT=0.3)

! Apply a time-varying load to the bodies and simulate the time-history response of the friction joint
IMPR_FONC_MULT(reuse=LOAD,
               MODELE=MODEL,
               CHAM_GD=CONTACT,
               FONC_MULT=(_F(
                   FONCTION=force_time_history,
                   GROUP_MA=BODY_1,
                   COEF_MULT=1.0
               ), _F(
                   FONCTION=displacement_time_history,
                   GROUP_MA=BODY_2,
                   COEF_MULT=1.0
               ))

! Solve the equations of motion for the system and compute the time-history response of the bodies
CALC_CHAMP(reuse=RESPONSE,
           MODELE=MODEL,
           CHAM_MATER=MATERIAL,
           CHAM_INIT=INITIAL_DISPLACEMENT,
           EXCIT=(_F(
               CHARGE=LOAD,
               TYPE_CHARGE='FONCTION'
           )),
           INCREMENT=_F(
               INST=time_step,
               CRITERE='RELATIF',
               PRECISION=0.01
           ),
           NEWTON=_F(
               MATRICE='TANGENTE',
               REAC_ITER=1,
               RESI_GLOB_RELA=1.0E-6
           ),
           ARCHIVAGE=_F(
               RESULTAT=result_file,
               FORMAT='ASTER'
           ))

So my question is what is the operator LIAISON_SOLIDE_SPH which supposed to be part of standard library bibmater_meca.
Bibmater_meca should be part of the standard libraries that are provided with the software, and it contains the LIAISON_SOLIDE_SPH command that is used to define a spherical solid joint between two bodies.

Where can I get information/literature/knowledge on obtaining and importing bibmater_meca and of course of the proper usage of operator LIAISON_SOLIDE_SPH.

Thank you and kind regards.

#5 Introduce yourself / Présentez vous » Salut \ Hello / Ciao » 2022-09-27 18:11:29

EnKiNekiDela
Replies: 0

Hello from Slovenija,

presently employed in Electric Utility, still a student interested in seismic dissipation devices development.
Investigating full 3D seismic isolators behavior hosting nuclear island, at the moment with non-linear dynamics.
This is my 3rd  exploration endeavor at choosing appropriate software for my research. 3 times the charm, they say.

Bonne chance

#6 Code_Aster usage » Modelling snubber element in 3D » 2022-09-08 19:20:12

EnKiNekiDela
Replies: 0

Hello,

since I am still very new to CA, I wonder if there are any experience at modelling snubbers. Snubbers can be usually represented as 2 node element with damping and stiffness properties in axial direction.
Connecting nodes can be fixed only in translation and/or rotations...

But how to model that if that 2 node element (snubber) is part and connects larger 2 meshes/superstructure, which are let's say rigid but one translates and rotates (large rotations and translations) during transient and snubber supposed to make a rigid link between them except in snubbers axial direction, which is governed with damping and stiffness.

Is there any other way to model that except with solid elements with orthotropic properties?

Thank you for your help.

#7 Re: Code_Aster usage » [SOLVED] DYNA_NON_LINE Damping/dissipation » 2022-09-08 18:54:57

Shortest answer after quite some experimenting is to introduce  material wit damping properties wisely and experiment with solver properties and precision of residuals at iterations....if model allows that.

#8 Re: Code_Aster usage » [SOLVED] Modelling Spherical joint with friction » 2022-09-05 08:59:32

There is workaround which is limited (level of compliance is yet to be determined) and requires constant calibrations with same but more complex model with CONTACTS:
1. introduce CABLE element and make it rigid in axial directions
2. on 2 nodes on CABLE element introduce discrete 1D element DIS_T, then apply  DIS_CONTACT properties over.
3. Have fun smile.

#9 Re: Code_Aster usage » Properties of a ball element » 2022-09-05 08:51:06

Hello,

regarding ball element I still haven't found any deeper explanation. Salome defines Radius for this ball element and Code_Aster understands it like 0D Element on node.

So my questions is:
does Code-aster at reading the mesh, reads also the radius properties of this 0D Element (ball element) and how it is used?

In presentation code-aster.org/V2/UPLOAD/DOC/Formations/07-structural_elements.pdf , there is  notation on 1D structural element "ball  joint  rods".

Are those ball  joint  rods just 1D elements like BARRE or CABLE, with 2 "ball joints" at each end unable to add any columb friction at those joint nodes? Or is there some other approach to model "ball joints" with internal friction.?

Temporal solution, since friction at rod ends plays major role in researched phenomenon is as following:
1.  model 2 contact  spheres  at each end of rod and then model rod, since POU_D_T just doesn't cope with moments between spheres and rod or in this case beam.
2.  wotk with CONTACT pnenomenon in nonlinear (DEFI_CONTACT...DYNA or STAT_NON_LINE)
3.  have major fun with convergence issues and calculation speed...

Any suggestions always greatly appreciated.

Regards

#10 Re: Code_Aster usage » [SOLVED] Friction spring modelling » 2022-09-05 08:47:31

After some time searching for the right answer to properly model friction springs, I came to solution of modelling it with simple DIS_CONTACT over SEG2 element, chosing RIGI_NOR, RIGI_TAN, and all other contact material properties properly, according to design requirements and constraining nodes to enable relative travel in desired direction. Attached the force/displacement test diagram.

#11 Code_Aster usage » Properties of a ball element » 2022-08-18 11:07:57

EnKiNekiDela
Replies: 1

Greetings dear colleagues,

would you be so kind and point me to documentation on syntax and use cases of ball elements (picture attached).

Thank you so much and best regards.

#12 Code_Aster usage » [SOLVED] DYNA_NON_LINE Damping/dissipation » 2022-07-24 15:08:41

EnKiNekiDela
Replies: 2

Greetings dear colleagues,

as I learn nonlinear analysis, having model combined with contact elements and large translations/rotations due to seismic motion, response increase (e.g. acceleration increase and spikes) became into play.

As of available documentation following damping/dissipation approaches are possible:
1. Material (behavior) dissipation
2. Dissipation in links, joints and assemblies (friction)
3. Modal damping (values from experiments)
4. Rayleigh damping (often fitted on modal damping values)
5. HF damping from the time scheme (if needed)

Due to contact elements, I am stuck with, it seems to me modal (3.) and Rayleigh damping (4.,  I am not completely sure of that) are off limits.
Dissipation with friction (2.) is present but limited on specific elements in structure.
So high response is still present at other sub-parts of structure as I have ELAS material.

So I intend to implement 1., 3. and 5.

Do yo have any experience on that matter like examples or existing CA documentation?
I am particularly interested in use of existing/verified non-linear materials: concrete and structural steel, since those are relevant for superstructure response and not for research of material non-linearity.
And what is your experience on calculation time using specific approaches?

Thank you so much and best regards.

#13 Re: Code_Aster usage » [SOLVED] Friction spring modelling » 2022-07-24 14:45:25

Thank you very much, this should be the answer.

#14 Re: Code_Aster usage » [SOLVED] Friction spring modelling » 2022-07-21 19:59:43

miib wrote:

U2.04.03

code-aster.org/doc/default/en/man_u/u2/u2.04.03.pdf


Thank you for you fast reply.
I was investigating the possibility of linear kinematic wok hardening, but since I have max. force/displacement 10MN/300mm, I wasn't sure this would work regarding the note from documentation:" This model (like all the models with linear work hardening) risks to over-estimate the constraints in the event of strong deformations, (or to underestimate the deformations with imposed constraint) because nothing limits the curve of work hardening."

Therefore I am searching for alternatives. Maybe I should try and check regardless.

#15 Code_Aster usage » [SOLVED] Friction spring modelling » 2022-07-21 14:18:20

EnKiNekiDela
Replies: 6

Greetings dear colleagues,

I was wondering if someone did manage to implement load/deflection behavior with different stiffness for loading/unloading as shown in the attached picture. Loading and /or unloading stage are assumed linear but not equal. It represents spring rings, with dissipative work due to internal friction.
It could be best to describe behavior just for 1D element, without assembling complex discrete mechanism.

Thank you for your help and ideas.

Regards

#17 Code_Aster usage » [SOLVED] Modelling Spherical joint with friction » 2022-06-20 20:15:18

EnKiNekiDela
Replies: 1

Greetings dear colleagues,

I have a problem to make a very simple model of Spherical plain bearing like attached picture.
In Code_Aster it is doable to model such a bearing with spherical contact surfaces, simulation for transitory analysis works as expected.
Problem arises in case of several hundred Spherical plain bearing instances in DYNA_NON_LINE, using the only to my knowledge allowable distribution method "Centralise" for parallel solving, making computation times very long...(cca 1 week+ at e.g. 14 MPI, 128 GB RAM for couple of seconds with very loose precision, resi_glob_rela, resi_glob_max, resi_frot)
So, my question is if exist there any simpler approach to model such a ball joint taking into consideration radius and friction of ball. It would be miracle if this could be done with simple node and beam model.
There is some ball element in Salome Meca for which I cannot find any documentation of its use (docs.salome-platform.org/7/gui/SMESH/adding_nodes_and_elements_page.html).

Any help in this direction would be greatly appreciated.

Thank you for your continuous efforts and stay safe.

#18 Code_Aster usage » [SOLVED] DYNA_NON_LINE working with absolute/relative displacements » 2022-03-27 19:35:25

EnKiNekiDela
Replies: 2

Hello everyone,

I am recently working on non-linear example of a seismic transient. R4.05.01 is discussing  equations of movement in absolute/relative reference marks.
My intent was to use absolute displacement time history as input (load_uxyz from Stage_2.comm in attachement).
Results are extracted from DEPL, ACCE fields (POST_RELEVE_T).
Now I am a bit lost on how to make sure inputs and received results are in the same reference mark (e.g.absolute) or where to check or set that.
Any suggested reference to appropriate literature to get knowledge on that topic is most welcome.

Thank you and best regards

#19 Re: Code_Aster installation » Problem with salome_meca-lgpl-2021.0.0-1-20210811-scibian-9 -> SIGSEG » 2021-12-02 20:53:38

Hello,

same issue with Loguru caught a signal: SIGSEGV...

At certain point started to appear and no matter what I do, even with files which worked previously, now it crashes constantly.

Started with 2021.0.0.1 and then I pulled 2021.0.0.2 sif, same issue.

All suggested workarounds failed (save as, make new,...).

Any ideas hugely appreciated.



hberro wrote:

Hello,

This issue will be fixed in version 2021.0.1

It is mainly encountered with code_aster v15 and due to the new concept naming in the pythonic version of code_aster.

If you can share the med result file I can verify it will be all good with the patched upcoming version.

HB

#20 Re: Code_Aster installation » Problem with salome_meca-lgpl-2021.0.0-1-20210811-scibian-9 -> SIGSEG » 2021-12-02 20:33:14

Hello,

same issue with Loguru caught a signal: SIGSEGV...

At certain point start to appear and no matter what I do, even with files which worked previously, now it crashes constantly.

Started with 2021.0.0.1 and then I pulled 2021.0.0.2 sif, same issue.

All suggested workarounds failed. Please find the attached rmed file.

Any ideas hugely appreciated.



hberro wrote:

Hello,

This issue will be fixed in version 2021.0.1

It is mainly encountered with code_aster v15 and due to the new concept naming in the pythonic version of code_aster.

If you can share the med result file I can verify it will be all good with the patched upcoming version.

HB

#21 Re: Code_Aster installation » Problem with salome_meca-lgpl-2021.0.0-1-20210811-scibian-9 -> SIGSEG » 2021-12-02 20:31:55

Hello,

same issue with Loguru caught a signal: SIGSEGV...

At certain point start to appear and no matter what I do, even with files which worked previously, now it crashes constantly.

Started with 2021.0.0.1 and then I pulled 2021.0.0.2 sif, same issue.

All suggested workarounds failed. Please find the attached rmed file.

Any ideas hugely appreciated.



hberro wrote:

Hello,

This issue will be fixed in version 2021.0.1

It is mainly encountered with code_aster v15 and due to the new concept naming in the pythonic version of code_aster.

If you can share the med result file I can verify it will be all good with the patched upcoming version.

HB

#22 Re: Salome-Meca installation » salome meca 2021 installation problems » 2021-11-14 10:49:06

Thank you so much for your guidance it helped a lot.

I am not sure why, but it did help creating launcher on desktop (I use xfce) pointing to salome_meca executable file, as running it from terminal results in my above mentioned general error.

For all finding typing sudo commands before start tedious this might help:

1. creating excutable e.g. salome.sh with:

#!/bin/sh -e
set -e
rm -r /dev/shm
mkdir /dev/shm
chmod -R a+rwx /dev/shm
exit 0

2. setting up crontab: https:_____//phoenixnap.com/kb/crontab-reboot" , putting in crontab file e.g.:
@reboot sleep 10 && /here_put_your_path_to_executable/salome.sh

3. making crontab service start on wsl2 startup, since it is stopped by default at each startup: https:____//askubuntu.com/questions/1165969/ubuntu-18-04-on-wsl-cron-daemon-not-running-after-reboot

There might be other ways to approach this, running salome.sh as service, but in my case those didn't work.

Regards

hberro wrote:

To be honest the output error is too generic to give you advice, did you follow the steps specific for WSL2 ?

#23 Re: Salome-Meca installation » salome meca 2021 installation problems » 2021-11-10 19:21:52

tested with proposal and now I got following errors...

lga@DESKTOP-R5TDPJ2:~/salome_meca$ ./salome_meca-lgpl-2021.0.0-1-20210811-scibian-9
not exist: /etc/krb5.conf
not exist: ${XDG_RUNTIME_DIR}
INFO:    Could not find any nv files on this host!
*****************************************************
INFO : Running salome_meca in software rendering mode
*****************************************************
runSalome running on DESKTOP-R5TDPJ2
Searching for a free port for naming service: 2812 - OK
Searching Naming Service  + found in 0.1 seconds
Searching /Kernel/Session in Naming Service  +++++Traceback (most recent call last):
  File "/opt/salome_meca/Salome-V2021-s9/modules/KERNEL_V9_7_0/bin/salome/orbmodule.py", line 181, in waitNSPID
    os.kill(thePID,0)
ProcessLookupError: [Errno 3] No such process

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/salome_meca/appli_V2021/bin/salome/runSalome.py", line 694, in useSalome
    clt = startSalome(args, modules_list, modules_root_dir)
  File "/opt/salome_meca/appli_V2021/bin/salome/runSalome.py", line 639, in startSalome
    session=clt.waitNSPID("/Kernel/Session",mySessionServ.PID,SALOME.Session)
  File "/opt/salome_meca/Salome-V2021-s9/modules/KERNEL_V9_7_0/bin/salome/orbmodule.py", line 183, in waitNSPID
    raise RuntimeError("Process %d for %s not found" % (thePID,theName))
RuntimeError: Process 4486 for /Kernel/Session not found


--- Error during Salome launch ---

...would apprecite any further suggestions, thanks in advance.

Edit: tried with python 2.7 and 3.6. Added "export LD_LIBRARY_PATH=/usr/local/Qt-5.15.3/lib:$LD_LIBRARY_PATH".


Regards

hberro wrote:

At one point during our tests on WSL2, we found it necessary to do the following

sudo rm -r /dev/shm
sudo mkdir /dev/shm
sudo chmod 777 /dev/shm

Hope it helps, let us know please.

HB

#24 Re: Salome-Meca installation » salome meca 2021 installation problems » 2021-11-07 17:12:03

Any news on this issue?

I tried with singularity SingularityCE 3.9.0 RC1 and Singularity 3.7.4 on wsl2 18.04. Same error as described already. Seems to stall on GUI as other continers work normally.

Thanks and regards.




mf wrote:

Hello,

you could try a newer version of singularity. A similar error has been reported with Ubuntu 18.04:

https:__//github.com/hpcng/singularity/issues/5466 (remove the __ no links allowed),

Mario.