Code_Aster ®
Version
8.2
Titrate:
Operator MODI_MODELE_XFEM


Date:
02/03/06
Author (S):
P. MASSIN, Key S. GENIAUT
:
U4.41.11-B1 Page:
1/4

Organization (S): EDF-R & D/AMA

Handbook of Utilization
U4.4- booklet: Modeling
Document: U4.41.11

Operator MODI_MODELE_XFEM

1 Goal

To modify a model by the introduction of specific finite elements which can be crossed by one
fissure.

This operator allows to modify certain traditional finite elements in finite elements nouveau riches;
elements to be modified were as a preliminary given by operator DEFI_FISS_XFEM [U4.82.08].
The new model thus defined could be useful in the continuation of calculations like datum input of
operator STAT_NON_LINE [U4.51.03] for example.

The operator produces concept of a model type.

Handbook of Utilization
U4.4- booklet: Modeling
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator MODI_MODELE_XFEM


Date:
02/03/06
Author (S):
P. MASSIN, Key S. GENIAUT
:
U4.41.11-B1 Page:
2/4

2 Syntax


[model] = MODI_MODELE_XFEM (


MODELE_IN

= Mo,








[model]


FISSURE = fiss,
[fiss_xfem]


CRITERE = 1.1E-4,






[DEFAUT]








crit,
[R]


INFO
=/1,







[DEFAUT]









/2,




)
Handbook of Utilization
U4.4- booklet: Modeling
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator MODI_MODELE_XFEM


Date:
02/03/06
Author (S):
P. MASSIN, Key S. GENIAUT
:
U4.41.11-B1 Page:
3/4

3 Operands

3.1 Operand
MODELE_IN

MODELE_IN
= Mo

Mo: name of the initial model on which one defined the fissure as a preliminary by the operator
DEFI_FISS_XFEM [U4.82.08].

This initial model is used as a basis for creation of the new model. It is advised to choose a name
different for the new model.

3.2 Operand
FISSURE

FISSURE = fiss

fiss: name of the fissure defined as a preliminary by operator DEFI_FISS_XFEM [U4.82.08].

3.3 Operand
CRITERE

CRITERE = crit

crit: actual value of the criterion allowing to the cancellation of the degrees of freedom (ddls) nouveau riches when
the fissure passes close to a node. When the fissure cuts an element 3D in two volumes, it
relationship between smallest volume and greatest volume should not exceed this criterion, if not,
that can cause problems of conditioning in the matrix of rigidity, and lead to
null pivots. Thus, if the criterion is exceeded, the ddls being able to lead to null pivots are
eliminated automatically. The default value of the criterion is based on simple tests
[R7.02.12].

3.4 Operand
INFO



/1: impression on file “MESSAGE”
· Stages of calculation
· Number of finite elements of the model


/2: even impression + impression for each mesh of the type of mesh enriched and by
its number of the type of finite element.

4 Example

FISS_ELLIPT = DEFI_FISS_XFEM (MODEL
= MOD_INITIAL,

............











)

MOD_ENRICH =
MODI_MODELE_XFEM
(MODELE_IN
= MOD_INITIAL,
FISSURE =
FISS_ELLIPT,
INFO =
2,)

Handbook of Utilization
U4.4- booklet: Modeling
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator MODI_MODELE_XFEM


Date:
02/03/06
Author (S):
P. MASSIN, Key S. GENIAUT
:
U4.41.11-B1 Page:
4/4

Intentionally white left page.
Handbook of Utilization
U4.4- booklet: Modeling
HT-62/06/004/A

Outline document