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#1 Re: Code_Aster usage » Mesh information extraction » 2016-10-29 11:26:32

Hoi Kevin

did you use the DEBUT(PAR_LOT='NON')?
See snippet below.


import sys
# assume ''construct_shell_thickness'' in folder:
cpath = sys.path
print 'length of cpath: ',len(cpath)
print 'current path: ',cpath
print 'current appended path: ',cpath[-1]

# reading initial mesh

#define shell (coque_3D) model;
# we have to add centre nodes with CREA_MAILLAGE


from construct_shell_thickness import *
from Utilitai.partition import *
import numpy
info = 2
ThicknessGroupShell = construct_shell_thickness(meshmod,info)

#2 Re: Code_Aster usage » Buckling analysis » 2016-10-29 10:54:14

http://caelinux.org/wiki/index.php/Cont … tressmodal

to keep it short: this is based on a previous version of CA. Some changes in the commands need to be made.

#3 Code_Aster usage » selection of transient thermal loads for static mechanical analysis » 2015-08-24 19:03:23

Replies: 1

Hoi forum,

after a transient thermal calculation I want to select a number of temperature fields from the results for applying a static thermal field as a mechanical load.
Unfortunately I cannot (ie I donot know how to) select a temperature field from the calculated fields.
For a static thermal analysis and the corresponding mechanical load I followed the training material: http://www.code-aster.org/V2/spip.php?a … ut&id=2018 wich works fine for me (except I didnot  change the mesh between thermal and mechanical).

The outline of the transient analysis is as follows:




                     AFFE=_F( TOUT='OUI',
                                  EVOL=ThRes,   ###<---- need for a selection, either time based or index based I guess


mechres = MECA_STATIQUE(MODELE = mechmod, 


I tried to change the EVOL=ThRES --> ThResXi in the AFFE_MATERIAU command by the result of CALC_CHAMP:

ThResXi = CALC_CHAMP(##reuse = ThRes,
                     ##TOUT_CHAM = 'OUI',
                     MODELE = ThMod,
                     RESULTAT = ThRes,
                     INST = 50000,);
                     #NUME_ORDRE = 5,);

without success.
resxyz = _F(RESULTAT=ThRes, TOUT_CHAM='OUI',INST=90000,),
works for me in the CALC_CHAMP command either.
I use Aster 13.0 for this analysis.

Any suggestions?
Thank you in advance.

#4 Re: Code_Aster usage » [Solved]Replace liquid py point mass » 2014-11-23 16:23:33

Hoi Reiteres

I used RBE3 to apply a moment to a cylinder once.
I used a massless node connected to the axial face of the cylinder by RBE3.
I still not convinced that RBE3 works well under ''all'' circumstances in C-Aster.

http://www.caelinux.org/wiki/index.php/ … rs/bc/rbe3

#5 Re: Code_Aster usage » Deleting Aster branch in Salome-Meca Object Browser » 2014-09-20 10:08:11

Hoi ffan

Interesting answer.
Could you enlighten us also?

alright, Jacopo just did that in this thread:

#6 Re: Salome-Meca usage » Salome / Aster / Carmel / Lamel » 2014-09-15 19:16:58

for what it's worth:

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#7 Re: Code_Aster usage » Angular accelerations » 2014-09-08 18:28:27

hoi allemaal

Summer is not over yet.

#8 Re: Code_Aster usage » Angular accelerations » 2014-09-07 08:50:05

Hoi Nikon

you cannot use angular acceleration in a static calculation.
Since an angular velocity already yields a (linear) acceleration in the part (and force dF = rho*dV*omega*omega), the forces caused by an angular acceleration will depend on the state and hence cannot be used in a static calculation.

#9 Re: Code_Aster usage » ANSYS to ASTER model and boudary condition translator » 2014-08-24 14:51:50

Hoi Nikon

you can try Femap for 45 days now.
http://www.plm.automation.siemens.com/n … liia400030
in dutch ;-), but German is available as well (and probably French and if you are in luck, english).

#10 Re: Code_Aster usage » Variable temperature for thermo_meca » 2014-08-04 18:33:00

hoi H.B,

if you provide us with the model (med, py input script or whatever you have available) or a typical example, we could help you.
A bit of fancy Python coding is -in most cases- nice to do.

#11 Re: Code_Aster usage » Variable temperature for thermo_meca » 2014-08-01 18:37:06

hoi H.B,

probably such an analyis is called a non linear analysis?
Non linear analysis can be performed by CA.

#12 Re: Code_Aster usage » Simple Linear Thermomecanical analysis Question. » 2014-07-02 19:17:40

Hoi Humberto

Humberto wrote:

Edit: I guess I should have started there, I just got lost reading comm files of test cases and the other documentation.

Overwhelmed by the abundance of data instead of (positive) matter.

#13 Re: Code_Aster usage » Simple Linear Thermomecanical analysis Question. » 2014-06-28 13:43:00

Hoi Humberto,

please have a look at the slide 16 and further:

http://www.code-aster.org/V2/UPLOAD/DOC … ermics.pdf


resproj = PROJ_CHAMP( RESULTAT=thresu,MODELE_1=thmodl, MODELE_2=thmodl2,)


mecres= MECA_STATIQUE(MODELE=mymodl,CHAM_MATER=mymat,EXCIT=_F(CHARGE=mecload,),)

[If I look carefully at the code I think there is a typo in the presentation: projres <--> resproj?]

The presentations are worth a look at:
http://www.code-aster.org/V2/spip.php?article282 (06_Thermics is selected above).

If you still have questions, return to this forum.

#14 Re: Code_Aster usage » Error after using LIAISON_RBE3 » 2014-06-25 19:32:04

Hoi Pierre-Arthur

pafortin wrote:

I think I am already applying your trick in my case as each master node corresponds to a mass M_TR_D_N element (with proper mass and inertia values).

Okee, I looked into your mail and comm files and after some searching I see that N35701 is coupled to P100317 in group CP100317 that carries a mass and inertia. Is this coupling alright?

pafortin wrote:

In your example, the mass and stiffness values are set to zero. Would it work with a different value ?
Your trick seems to suggest that efforts can be applied through a RBE3 element only if the master node has been affected with a mass or stiffness property (even if the value is zero). Am I understanding you correctly ?

If it works for zero, it should work with any (positive) value.
I would assume that only a mass or only a stiffness attached to a node would be enough (as long as the element has rotational dofs if you need them).

Can you reproduce the error with a small model?
Or just adding one RBE3 constraint (and possibly a mass to the master node directly) and see what happens?

#15 Re: Code_Aster usage » Error after using LIAISON_RBE3 » 2014-06-24 20:21:35

Hoi Pierre-Arthur

I used the RBE3 command once for applying a torque to a solid and I had to use some trick on the master node.
Because a 3D node will only carry translations, no rotations, you can add a ''mass and/or stiffness'' element to it to get the rotational dofs:



I did have a glance at your mess file and I am not sure whether you applied this ''trick'' or not and whether it has to be used in your case.
Your code being eg (line 2503 of the mess file):


<guess>: I ''think'' you did not apply this ''trick''. From the two master nodes the 3 rotations cannot be determined. </guess>
Is your slave group always fit (no co-linear nodes) to determine the eg DDL_MAIT=(DX','DY','DZ','DRX','DRY','DRZ',) from the  DDL_ESCL=..?
I must say the error message does not indicate such an error.

#16 Re: Code_Aster usage » How to fix the theta direction in a local cylindrical coordinate » 2014-06-19 18:50:39

Hoi Baimao

you can have a look here to restrict nodes in certain directions, though not by a cylindrical coordinate system:

http://www.caelinux.org/wiki/index.php/ … pythonlist

#17 Re: Code_Aster usage » hyperelastic » 2014-03-16 20:04:35

Hoi manolo,

I think the only shell element capable of hyper elasticity is coque_3d, not DKT.


I cannot find the overview right now (ie too lazy to  dive into the manuals), but I guess changing 'DKT' into 'COQUE_3D' will take you further (and donot forget to change the mesh into tria7 or quad9).

#18 Re: Code_Aster usage » RBE3 behaviour » 2014-02-08 17:41:13

Hoi Richard, Onno,

thanks for the comments.

The moment you apply on the Master node is applied as nodal forces to the slave nodes with weighting factors depending on the distance from the center of gravity of the slave nodes.
In your case this is the same for all nodes (R).
In the areas with a dense mesh the force distribution is higher and thus leads to the observed deformation of the cylinder.

I was hoping that the RBE3 would not depend on mesh density. And like the Ansys example shows, may be it should not.
The case using the solid-mesh connection indeed shows that this implementation does not depend on the mesh density.
I will have a look at the Code-Aster implementation, although I recall that the last time I read it, I cannot judge whether it can be made independent of the mesh density easily ( http://www.code-aster.org/V2/doc/defaul … .03.08.pdf ).

Anyway, if used carefully, RBE3 can be / might be an effetively tool.

#19 Re: Code_Aster usage » [Discussion] How to model a hinge bc allowing large rotations » 2014-02-01 12:19:59

Hoi Richard

Two remarks:


In my oppinion there would be two valid approaches to solve this:
1) Allow applying DOFs in a cylindrical coordinate system
2) Implement GROT_GDEP for BARRE elements

It would be nice if more elements would have large displacement behaviour in C-Aster.

Does RBE3 support large deformation in C-Aster? I havenot really looked into detail for that part of RBE3, but I guess it does not (recalling that some constant matrix calculation is used). Lately I used and RBE3 to apply a load to a face (torque on axial face of cylinder) but it did not behave really well.

Edit, though a bit off topic:
RBE3 may be used in a linear case to define a hinge behaviour. See:
http://www.caelinux.org/wiki/index.php/ … onstrained (under construction at this moment)

#20 Re: Code_Aster usage » RBE3 behaviour » 2014-02-01 10:13:16

A picture of the local deformation.

#21 Code_Aster usage » RBE3 behaviour » 2014-02-01 10:05:56

Replies: 5


after reading this post http://www.code-aster.org/forum2/viewtopic.php?id=18439 I tried the RBE3 command myself.
Onnomobile is satisfied with the behaviour, but I run into problems when using an asymmetric mesh.
I used the RBE3 command to apply a torque on the axial face of the cylinder. For a symmetric mesh it really works fine, for an asymmetric mesh the behaviour is less satisfactory. Maybe it is because of my adjustments of the RBE3 command:


I apply the torque to the master node Nmaster. The nodes of the axial face 'Abot' of the cylinder are contained in 'Nbot'.
The complete command file is attached (it will not run because of lack of additional files, but see next line).
Further details can be found here: http://www.caelinux.org/wiki/index.php/ … ue_by_RBE3.

Did I use the wrong settings for this command or is it inherent to the RBE3 connection with asymmetric mesh?
The nice part is that using the transition of the poutre-3D-solid just works fine for both cases:

replace LIAISON_RBE3=.... by:

#22 Re: Code_Aster usage » publication of my book "Beginning with Code_Aster" » 2013-12-08 11:55:13

Hoi jean pierre

Very nice overview of code aster and related programs.
Handy to have a printed version of many frequently used commands and keywords, explanation and how to use them.
Thank you very much for the effort.

#23 Re: Code_Aster usage » Stresses from Coque_3D ? » 2013-10-25 10:34:59

Hoi Anders

I figured it out. Due to my inexperience with the software, I didn't realize that I needed to specifiy result files for 81 and 82 as well.

That should be noticed by a copy error in the *.mess file.
Postpro is not available anymore in Salome7.X. So paraviz will be the future I presume.

#24 Re: Code_Aster usage » Stresses from Coque_3D ? » 2013-10-21 20:14:02


that example is for pre C-A11.4.
These may be used with C-A11.X, depending on what postprocessor you like [postpro or paravis]:

http://www.caelinux.org/wiki/index.php/ … /plotcoq3d


http://www.caelinux.org/wiki/index.php/ … q3dparavis

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