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**PATCH**- Replies: 2

Hi everyone,

I would like to produce structured mesh including prism and hex elements. I thought that if I mesh surface correctly and then used 3D extrusion meshing algorithm it will work. It doesn't.

Can somebody help solving this meshing problem? Any ideas?

Thank you.

Hi everybody,

Can anybody help with this topic? I am enclosing my current progress with this analysis. Currently the analysis runs but gives me zero response which is not correct .

Thank you in advance.

PATCH

**PATCH**- Replies: 8

Hi,

I am new in frequency domain analysis in Code_Aster so I would like to create basic analysis. I am working regularly in Abaqus and running *Steady state dynamics to evaluate fixture performance. For this purpose I create MPC to all bolts holes that holds fixture and load control point with acceleration 1g load (9.81 m/s2) and check how fixture amplifies the signal in different locations.

My question is how can I simulate this in Code_Aster? Do you have any examples?

Thank you in advance,

PATCH

Yes you are right. Thank you for adding those necessary information especially

`DEBUT(PAR_LOT='NON')`

Regards,

PATCH

I have figured out the solution. You can use try-except statements and if the solution fails, use predefined results as output (loading it from a file). Here is a snippet of code.

```
try:
RESU_S=SIMU_POINT_MAT(COMPORTEMENT=_F(RELATION=MODEL,),
MATER=AA2024,
INCREMENT=_F(LIST_INST=INST_S,),
NEWTON=_F(REAC_ITER=1,),
CONVERGENCE=_F (ITER_GLOB_MAXI=40,),
SUPPORT='POINT',
SIGM_IMPOSE=_F(SIXX=S_1,),
INFO=1,);
RESP_S=CALC_TABLE(TABLE=RESU_S,
ACTION=(_F(OPERATION='FILTRE',
NOM_PARA='SIXX',
CRIT_COMP='GE',
VALE=1.0,),
_F(OPERATION='FILTRE',
NOM_PARA='INST',
CRIT_COMP='GE',
VALE=TIME_S[-20],),
_F(OPERATION='EXTR',
NOM_PARA=('INST','EPXX',),),
),);
except:
print('Nastal problem s konvergenci, musim to nahradit FAKE !!!')
ERR_S=LIRE_FONCTION(INDIC_PARA=(1,1,),
INDIC_RESU=(1,4,),
UNITE=49,
NOM_PARA='INST',
NOM_RESU='EPXX',
INTERPOL='LIN',);
RESP_S=CREA_TABLE(FONCTION=_F(FONCTION=ERR_S,),);
```

Regards,

PATCH

**PATCH**- Replies: 3

Hello,

I am working on constitutive model calibration using macro MACR_RECAL and using SIMU_POINT_MAT in slave file. I have stress loading of one material point and I am getting convergence issues. Since I am using MACR_RECAL all calculations must converge and return values. I have been wondering if there is a way of using Python IF statement in case when solution diverges. If the solution will diverge I will return manually created results.

Regards,

PATCH

**PATCH**- Replies: 0

Hello,

I am solving rotor dynamics problems and I want to solve harmonics analysis of rotor with unbalance and foundation excitation.

As a first step I have performed modal analysis of this rotor for multiple rotation speed and constructed Campbell diagram. In this type of analysis I was able to change stiffness and damping parameters of rotor with each speed (as proposed in U2.06.32 section 3.2.3). But how can I make it work in case of harmonic or transient analysis. I can not use for loop for changing bearing parameters. Is there any robust way how to do it?

Regards,

Michal

Hi,

have you managed to complete the tutorial on rotating machine from zero to the end?

Michal

**PATCH**- Replies: 0

Hi,

I am starting with rotor dynamics and I have started with test cases. In past I have been using ANSYS so first I have checked ANSYS Verification manual, where is example VM247 which is comparable with Code-Aster example SDNV110. Unfortunately C-A example is done using volume elements and Ansys is done using beam elements. I have been trying to compute analysis using beam elements in C-A but I am having some problems with results.

I am getting some warning during computation and I do not know their meaning and then I am getting too high frequencies and wrong shape of curves in Campbell diagram.

Whirl speeed for slope = 1 (from ANSYS manual):

Mode 1: 15470 RPM

Mode 2: 17159 RPM

Mode 3: 46612 RPM

Mode 4: 49983 RPM

...

I am enclosing necessary files for analysis run if somebody will be willing to help. Thank you.

Regards,

Michal

**PATCH**- Replies: 0

Hi,

I have been searching trought documentation of CA and I have found interresting tool for Rotordynamics. It is called EDYOS which should be part of CADYAC package. Here are two presentation with use of those tools.

Do you know where to get those tools or if it will be implemeted in Salome or CA?

Thank you,

Michal

Thank you very much. It worked.

Regards,

Michal

**PATCH**- Replies: 2

Hello,

I am working on a problem, where I need to use deformed mesh in other calculations. I need to load mesh and then make this loaded mesh as input mesh to next analysis. This procedure works nicely when using linear material, but it creates wierd deformed shape when using nonlinear material (linear isotropic hardening). Problem is in place of boundary conditions. Do anybody knows how to solve this problem? I am enclosing ilustrative pictures and input files.

Regards,

Michal

Well ... You are right. I was using this command in Batch window after computation. Your example works fine. Thank you.

What is you aim of calibration? I am trying to calibrate Chaboche model with other possible extension available in C-A.

Regards,

Michal

Hi,

I have also found this in documentation, but it does not work. I am getting enclosed error.

I am enclosing files of 'calibration'. This parth should work fine if you increase number if allowable iterations and population size. This is just testing version to get faster some reuslts and be able to save them using

-interact

to variables and work with them.

Regards,

Michal

Thank you for your help. Now it works fine.

I have another question. Is there any way how to extract resulting (fitted) parameters from MACR_RECAL? I mean if i save reuslts to lets say:

RESULT = MACR_RECAL( ... ) then save just parameters to file or to variables using python.

Regards,

Michal

Thank you for reply.

I am not able to get results uisng SIEF_ELNO, I do not know how to plot results in ParaVIS. But I have done it different way. I have read documentation of CALC_CHAMP again and I have found in section 2.9.1 Operand FORCE, Noteice 2. It says:

If the keyword GROUP_MA is informed, the options «FORC_NODA» and ' REAC_NODA ' are computed as follows: Fk is only computed on the elements requested then assembled. The result is different from a global computation on all the field then reduced to the required elements. The established method allows to gauge the reaction of a part of model on another.

This solved my problem of getting results. But still do not know how to do it using SIEF_ELNO and N, VY, VZ, Mt, MFY, MFZ.

Michal

**PATCH**- Replies: 3

Hi.

I have a question about plotting or printing nodal forces of internal node. For example i have a beam fixed on one side a loaded with axial force on the other side.

I can obtain forces in ending nodes (node of applied boundary conditions) but I can not get forces of internal nodes. I understand that numerically there has to be zero force to comply force equilibrium because node belongs to adjoining elements.

Can I somehow select element and then obtain forces of this node? Now it will not be zero. On one of the adjoined elements forces will be positive and on the other one they will be negative.

Is there some way how to do it? I was doing this ANSYS APDL so I know it is possible.

Thank you in advance.

Michal

Hi.

I have the same problem. Did you figure out how to calculate internal forces?

Michal

Here is image with results.

**PATCH**- Replies: 9

Hi to all.

I am trying to use macro MACR_RECAL to obtain material parameters for Chaboche material model. But I am having some difficulties obtaining results. Results are totally wrong, I am not getting even right trends of data evolution.

What I have are three different strain controlled experimental curves and I am computing model responses using SIMU_POINT_MAT. Simulations are fast, but wrong .

I am including all necessary files to run the calibration. I have tried also different optimization method - HYBRIDE, to better map space of parameters but without any results.

Thank you for any advices.

Michal

So I have managed to map values of stress on subpoints in ParaVIS using IMPR_RESU_SP command. Can I do the same with strains?

Or in the best case, can I plot results as it will be on solid elements (show 'real' geometry a map results on it) so I can better interprate the results on inner and outher surface of pipe.

Michal

**PATCH**- Replies: 2

Hi.

I have some issues with TUYAU_6M elements. I am still getting this error:

!----------------------------------------------------------------------------------------------!

! <EXCEPTION> <CALCUL_23> !

! !

! Erreur utilisateur dans un calcul élémentaire : !

! Des caractéristiques d'"orientation" sont nécessaires sur la maille : M455 !

! - option de calcul élémentaire : RIGI_MECA !

! - type_élément : MET6SEG3 !

! !

! Conseils : !

! * Peut-être avez-vous oublié de renseigner le mot clé CARA_ELEM dans la commande courante. !

! * Dans la commande AFFE_CARA_ELEM, avez-vous affecté des caractéristiques d'"orientation" !

! sur la maille incriminée ? !

!----------------------------------------------------------------------------------------------!

Can you help me out? I am enclosign comm and other files.

Do you think it might be caused by geometry? I have one edge with opposite direction then others.

Thank you.

Michal

Thank you.

Can you provide .comm file?

Hi.

Did you figure out how to plot cross section in Paravis? I also have this problem and can not find it anywhere.

Regards,

Michal

**PATCH**- Replies: 0

Hello.

Can somebody help with my problem? I am trying to model axisymmetric analysis and load one edge (set of nodes) trough one master node (coupling of DOF). Something like in this tutorial:

http://caelinux.org/wiki/index.php/Cont … ses/torque

In tutorial they are performing 3D analysis and using command LIASON_SOLIDE, how can i do the same in 2D AXIS analysis?

Thank you in advance.

Regards,

PATCH

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