MAZARS model

pbiagini

Bonjour,

i'm trying to model a masonry cantilever with a MAZARS model. I have an elastic layer at the base and 40 m of masonry modeled with MAZARS law. It seems that the program doesn't apply the elastic material to the base layer, as indicated in the .comm file. The run stops with the following error:

CR d'execution de JDC en MIXTE

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

! ~~Exception utilisateur levee mais pas interceptee. !~~

! Les bases sont fermees. !

! Type de l'exception : error !

! !

! comportement MAZARS non trouvé pour la maille M3973 !

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

fin CR d'execution de JDC en MIXTE

I cannot understand why it tr to apply the MAZARS law even to the base layer. I post my model

Does anyone has any suggestion ?

Thank you very much
Attached file:
mensola_40m.zip, 45029kb

sébastienmeunier

Hello,

MAZARS model exists only for mesh elements group MENSOLA. So you should precise GROUP_MA=MENSOLA under COMP_INCR.

Regards !

pbiagini

Thank you very much for your prompt reply Sébastien !!!! I've forgotten to update this field.

Greetings,

Paolo

nirmaljoshi

Thanks for the post; eventhough 6 years later, I found it useful.

Is there any easy to understand literature for Mazar model's parameters?

GPSalachs

Hello, i am too working in a model with Mazars Model. I found useful the following documents.

If you have further insights in the parametrization of the Model please post them, everything is useful.

u4.43.01.pdf

r7.01.08.pdf

u4.51.11.pdf

nirmaljoshi

Hi GPSlachs,

Thanks for pointing towards the document. Do you have any related literature or simple worked out example of this model?

GPSalachs

I found interesting the book "Computational Modelling of Concrete Structures" Gunther Meschke, Bernhard Pichler.

You can also look in the code-aster.org documentation for the examples that apply the Mazars Model!

Edit: Also look into this post from 2014 : code-aster.org/forum2/viewtopic.php?id=20005

GPSalachs

I have a question regarding the threshold of damage parameter of the Mazars Model.

When the model i am making is in milimetes, does the threshold of damage also need to be calculated in milimeters?

nirmaljoshi

Today i was running the model with similar case. The model ran only when i made mesh in meters.

GPSalachs

Did you use pilotage to make your case or DDL_IMPO ?

I am asking because i am trying to make it run by running a force with a ramp function.

Do you apply also self weight with Mazars Model of damage?

GPSalachs

If i have a continuous 3D medium and i want to use Mazars Model should i assign with the command AFFE_CARA_ELEM an element to the

medium and while at that should i define an initial analysis with MECA_STATIQUE and a secondary analysis with STAT_NON_LINE to get the

initial linear part and the secondary non linear part of the material right?

nirmaljoshi

It seems DEFI_MATER_GC (U4.42.07) is easier and convenient to assign Mazer model. Did you try?

GPSalachs

No haven't tried the DEFI_MATER_GC (U4.42.07) command because i want to remain and understand first better the DEFI_MATER command with mazars model .

nirmaljoshi

Actually DEFI_MATER_GC is converted to DEFI_MATER during analysis and parameters (used by DEFI_MATER) is printed in the output file e.g.

C30_EC2 = DEFI_MATER_GC(RHO=2400.0,
MAZARS=_F(CODIFICATION='BAEL91', FCJ=3.9000000E7, UNITE_CONTRAINTE='MPa',),
INFO=1,)

== Paramètres of the model MAZARS [MPa] ==

Partie elasticity:

E = 3.73031085E+06, NU = 2.00000000E-01, RHO = 2.40000000E+03,

Nonlinear part:

BT = 1.59414953E+00, AC = 2.79632486E-03, SIGM_LIM = 2.34000000E+07, AT = 9.00000000E-01,

BC = 1.68155462E+01, K = 7.00000000E-01, EPSI_LIM = 3.50000000E-03,

EPSD0 = 6.27293728E-01,

For information:

FCJ = 3.90000000E+07, FTJ = 2.34000060E+06, EPSI_C = 2.10253884E-01,

==================================================
/
This method may be useful to understand the material-model although this is like reverse engineering.. ;)

GPSalachs

I made some tests indeed it feels easier to do it with the DEFI_MATER_GC command!

On another part tho, the curves one produces in 3D should be taken from the forces and plastic deformations? So like FORCE_REAC and EPSP ? Or am i considering something wrong here? I ask that cause if i take the DX,DY or DZ components they give linear results so i don't know if i am doing wrong somewhere or am i confronting something wrong..

Thank you!

nirmaljoshi

You can use Linear plus Non-linear analysis with STAT_NON_LIN alone. No need to use MECA_STATIQUE. Also, you need to define COMPORTMENT in STAT_NON_LIN to make the material behave as non-linear.

GPSalachs

Hello, thank you for the response.

My problem is that i define the comportment as MAZARS in STAT_NON_LINE and run the analysis but the DEPL i get is almost always linear and i don't really understand the why.

I am attaching the .comm and .med files for further insights and discussion!
Attached file:
comp.tar.xz, 6720kb

nirmaljoshi

1D mazar model in excel with stress strain relationship.
Attached file:
mazarModel.xlsx, 42911kb

nirmaljoshi

I am fining difficulty to converge the calculation. Is there any special way to make the calculation convergent rapidely?

GPSalachs

Yes i am too finding it difficult to make converge this kind of calculation. I do not know if the problem lies with the elements of the mesh (HEXA8) or something else entirely.It could be also some mistake i am making in the STAT_NON_LINE command regarding the comportment or the algorithm for the resolution. I have tried concatenating two STAT_NON_LINE commands or piloting it but the results do not give me the post peak curve.

And i too am trying to understand how to make it converge..

Could it be an orientation issue here? Or maybe the '3D' type of modeling?

~~Next Page »~~