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## #1 2021-11-11 16:46:03

GuillermoBarraza
Member
Registered: 2016-05-24
Posts: 47

### HELP: usage of PENE_MAXI in DEFI_CONTACT when ALGO_CONT='PENALISATION'

Hi everyone,

I have a question on how to use PENE_MAXI in a contact zone within DEFI_CONTACT when the Penalization contact algorithm and ADAPTATION='ADAPT_COEF' are selected.

According to the documentation (code-aster.org/V2/doc/v14/fr/man_u/u4/u4.44.11.pdf) the penalization coefficient (COEF_PENA_CONT) will be updated in every contact iteration in order to satisfy the maximum allowed penetration (defined by PENE_MAXI). It also says that if PENE_MAXI is not defined, Code_Aster will automatically set it as 1e-2 times the minimum edge of the underlying contact zone. However, no matter what value I assign to PENE_MAXI, it seems that the contact penetration is always going to values of ~1e-3 all the time (which makes me believe that it's always using the default value).

Here is the relevant extract of the .comm file:

``````CONTACT  = DEFI_CONTACT(MODELE         = MO,
FORMULATION    = 'CONTINUE',
ALGO_RESO_CONT = 'POINT_FIXE',
#ALGO_RESO_FROT = 'POINT_FIXE',
ALGO_RESO_GEOM = 'POINT_FIXE',
LISSAGE        = 'OUI',
#FROTTEMENT     = 'COULOMB',

ZONE =(
_F(
GROUP_MA_MAIT ='FIL_MAI1',
GROUP_MA_ESCL ='LOP_ESC1',
CONTACT_INIT  = 'INTERPENETRE',
GLISSIERE     = 'OUI',
#COULOMB       = 0.,
),
_F(
GROUP_MA_MAIT ='LOP_ESC2',
GROUP_MA_ESCL ='FIL_MAI2',
ALGO_CONT = 'PENALISATION',
#COEF_PENA_CONT = 1.E4,
ADAPTATION='ADAPT_COEF',        # <------------------- HERE
PENE_MAXI=300,                              # <------------------- and HERE
#COULOMB=0.,
),
),
);``````

I also read somewhere in the source code that when ALGO_RESO_CONT = 'POINT_FIXE', the value of the penalization coefficient is updated, but the residuals are never checked. Therefore, the max penetration is never considered as a convergence criteria, why is that?

Does anyone have experience with this setting in the contact definition with CONTINUE formulation? I would really appreciate any insights into how to interpret the residuals given by this option, as well as clarifying why is the PENE_MAXI not respected.

I've been using the benchmark ssnv504k (code-aster.org/V2/doc/v14/fr/man_v/v6/v6.04.504.pdf) to test the effect of changing PENE_MAXI. To save you some time, attached are the needed files for the simulation.

Thank you in advance,

Guillermo

Last edited by GuillermoBarraza (2021-11-16 13:37:41)

Attachments:
ssnv504k.zip, Size: 53.49 KiB, Downloads: 34

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