Code_Aster ®
Version
8.2
Titrate:
Operator PROJ_CHAMP


Date:
31/01/06
Author (S):
J. Key PELLET
:
U4.72.05-F1 Page:
1/8

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

Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
Document: U4.72.05

Operator PROJ_CHAMP

1 Goal

To project the fields with the nodes of a structure of data result on another grid. This
command can be used for example to transfer on a “mechanical” grid, the result of a calculation
thermics carried out on a “thermal” grid different. One can also continue a calculation
thermics (or mechanics) on another grid (more or less refined).

The command makes it possible to define “zones” (geometrical) which one projects the ones on the others
what makes it possible to solve the problem of a desired discontinuity of the field projected (for example it
length of the lips of a fissure).

In a more anecdotic way, the command also makes it possible to project the fields by elements
“ELNO” and “ELEM” (see [§3.7]) but this possibility is of less interest. In the same way, methods
(disadvised) “NUAGE_DEG_0/1” make it possible to create “insulated” cham_no_ *

Product a structure of data SD_RESULTAT (or exceptionally cham_no_ *)
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator PROJ_CHAMP


Date:
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Author (S):
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:
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2 Syntax

resu = PROJ_CHAMP
(

# Use of the functions of form of the 1st model (method strongly
advised):

/
METHODE=
“ELEM”
,
[DEFAUT]





RESULTAT
= evo1
,
/
[evol_ther]

















/[evol_elas]

















/[evol_noli]

















/[evol_char]

















/[mode_meca]

















/[mode_stat_depl]

















/[base_modale]



MODELE_1
= mo1
,
[model]



MODELE_2
= mo2
,
[model]




CAS_FIGURE =
/
“3D”,



/“2D”,
/“2.5D',
/“1.5D',





# Selection of the names of the fields
/
TOUT_CHAM
=
“OUI”
,
[DEFAUT]
/
NOM_CHAM
=
l_noch
,
[l_Kn]



# Selection of the sequence numbers
/
TOUT_ORDRE =
“OUI”
,
[DEFAUT]
/
NUME_ORDRE =
l_nuor
,
[l_I]




/
/INST =
l_inst
,
[l_R]
/
FREQ =
l_freq
,
[l_R]






/LIST_INST
=
l_inst
,
[listr8]






/LIST_FREQ
=
l_freq
,
[listr8]





| PRECISION
=/prec,
/
1.0E-3
,
[DEFAUT]






| CRITERION =/“RELATIVE”
, [DEFAUT]
/
“ABSOLU”
,




DISTANCE_MAX
=
d_max,


[R]




ALARME
=
/
“OUI”,


[DEFAUT]
/'NON,





PROL_ZERO
=
/
“NON”,


[DEFAUT]

TYPE_CHAM
= “NOEU”







# if the projected SD is of type “mode”:





RIGI_MECA
=
kass [matr_asse]






MASS_MECA
=
farmhouse [matr_asse]






AMOR_MECA
=
aass [matr_asse]


# “Smoothing” of a scatter plot (strongly disadvised method!)

/METHODE=/“NUAGE_DEG_1”
,






/
“NUAGE_DEG_0”
,





CHAM_NO =
chno1
,
[cham_no_ *]




CHAM_NO_REFE
=
chno2
,
[cham_no_ *]


VIS_A_VIS
= (_F (






| TOUT_1
=
“OUI”
,







| GROUP_MA_1 = lgma1, [l_gr_maille]







| MAILLE_1
=
lmail1
,
[l_maille]







| GROUP_NO_1 = lgno1, [l_gr_noeud]







| NOEUD_1 =
lnoe1
,
[l_noeud]
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator PROJ_CHAMP


Date:
31/01/06
Author (S):
J. Key PELLET
:
U4.72.05-F1 Page:
3/8








| TOUT_2
=
“OUI”
,







| GROUP_MA_2 = lgma2, [l_gr_maille]







| MAILLE_2
=
lmail2
,
[l_maille]







| GROUP_NO_2 = lgno2, [l_gr_noeud]







| NOEUD_2 =
lnoe2
,
[l_noeud]







CAS_FIGURE =
/
“3D”,



/“2D”,
/“2.5D',
/“1.5D',



),),


SENSIBILITE
=

will listpara
,
[l_para_sensi]


TITER
= titr,
[l_Kn]







);

Type of the result of the operator:
if one uses key word CHAM_NO, resu is a CHAM_NO of the same size as chno1,
if one uses key word RESULTAT, resu is a standard SD_RESULTAT in the same way than evo1.

Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator PROJ_CHAMP


Date:
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Author (S):
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:
U4.72.05-F1 Page:
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3 Operands

3.1 Operand
METHODE

Two families of method of projection of the nodes of a grid on another grid are
available.

First family (ELEM) is traditional: to calculate the value on a node of the new grid,
one seeks in which element of the old grid this node is, then one interpolates the value with
assistance of the functions of form of this element. When the node is not in one of the elements of
the old grid (apart from the fields geometrical modelled), the method connects the node
and the point of the element nearest and interpolates the value using the functions of form of
the element. There is thus (by defect) a “prolongation” of the field outside the initial grid.
Operand DISTANCE_MAX makes it possible to modify this behavior.

The second family (NUAGE_DEG_1/0) (strongly disadvised) uses the concept of clouds of
points, by forgetting the finite elements present in the models. It is more general than the family
(ELEM) because it makes it possible to project a field with the nodes without these nodes being carried by
finite elements (for example a whole of sensors). On the other hand, this family often disturbs them
users familiar of the finite element method because it is purely geometrical and does not see
material borders nor holes: the computed value on a node of the new grid depends on
all the nodes which are close for him. In the zones of strong gradient, the values can be
obtained with a strong extrapolation, which is seldom very “physical”.

3.1.1 Limitations

Method ELEM treats the fields with the nodes of the SD_RESULTAT.
Method NUAGE_DEG_1/0 can treat only the insulated fields (and not SD_RESULTAT).

3.2 Operands
CHAM_NO and CHAM_NO_REFE

The command projects the values of the cham_no chno1 on the nodes of the grid subjacent with
“model of field”: chno2.

It created then the cham_no result on the same model as chno2 (same components carried
by the same nodes) but with values obtained by “interpolation” of the values of chno1.

One can project a cham_no a priori does not matter that it real or complex size, in 2D or in
3D. The field to be projected and the model field must be of the same type (DEPL_R, TEMP_R,…).

The field result will be then of the same type.

3.3 Word
key
VIS_A_VIS

This key word optional factor makes it possible to project the field “per pieces”. By defect, it is the unit
field which is projected.

This key word makes it possible to project discontinuous fields or to solve the problem of the projection of
complex models (see [§3.3.3]).

If it is used this key word allows the user to project a field a priori discontinuous (on a line or
a surface) and to preserve this discontinuity for the projected field:

Z1
O
With
B
Z2

Appear 3.3-a
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

Code_Aster ®
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Titrate:
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Date:
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For example, that is to say the fissured structure of [Figure 3.3-a]. The field of displacement is discontinuous
on the fissure: the upper lips and lower although geometrically confused have
each one their own field of displacement.

Let us suppose that one has 2 grids (M and Me) different from this structure and that for each one
of these grids, the Z1 zones and Z2 are represented by two named GROUP_MA Z1 and Z2.

One will be able to write:


VIS_A_VIS = (
_F ((GROUP_MA_1 = “Z1”, GROUP_MA_2 = “Z1”
),
_F
(GROUP_MA_1
=
“Z2”
,
GROUP_MA_2
=
“Z2”),

The values of the field projected on the upper lip (pertaining to Z1) will only hold account
values of the initial field on Z1. In the same way the values obtained on the lower lip do not depend
that initial field on Z2.

Note:

On line OB, the nodes are not duplicated their values will be calculated twice
(for the 2 occurrences of VIS_A_VIS). It is the last occurrence which will impose its
value.

3.3.1 Operands
TOUT_1/GROUP_MA_1/MAILLE_1/GROUP_NO_1/NOEUD_1

These operands are used to define the whole of the meshs (“ELEM”) or of the nodes (“NUAGE…”) in
to take into account in the initial grid.

3.3.2 Operands
TOUT_2/GROUP_MA_2/MAILLE_2/GROUP_NO_2/NOEUD_2

These operands are used to define the whole of the nodes where the field is evaluated.

3.3.3 Use of key word VIS_A_VIS to project the complex models

Key word VIS_A_VIS makes it possible for example to solve the problem of the projection of a field of
temperature calculated on a model containing of the elements 3D and the elements of hull (a solid
whose skin interns would be covered with a “liner” with a grid in elements of hull).

The problem is as follows: the elements 3D carry on their nodes the only degree of freedom TEMP,
whereas the elements of hull (thermal) carry the 3 degree of freedom: TEMP, TEMP_INF and
TEMP_SUP. If one does not take precautions and that one projects all the model of only one blow, them
degree of freedom TEMP_INF and TEMP_SUP “will be lost” during projection. Indeed, like
initial grid contains elements voluminal, it is the procedure “3D” which is applied: for
each node of grid 2, one seeks a voluminal mesh which contains this node (or which in is
near). Once this found mesh, one interpolates the degrees of freedom carried by all the nodes of
this mesh. Practically, no mesh 3D can carry on all its nodes the degrees of freedom
TEMP_INF and TEMP_SUP; those are thus lost.

To solve this problem it is necessary to do something like:

evo2= PROJ_CHAMP (RESULTAT=evo1,…
VIS_A_VIS= (_F (GROUP_MA_1: “VOLU”, GROUP_MA_2=' VOLU',),


_F (GROUP_MA_1:
“LINER”
,
GROUP_MA_2=' LINER',),)

In this manner, the meshs of “LINER” of grid 2 will be affected by the values carried by
the meshs of “LINER” of the grid 1 and they will carry the same degrees of freedom.
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

Code_Aster ®
Version
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Titrate:
Operator PROJ_CHAMP


Date:
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Author (S):
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:
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3.4 Operand
RESULTAT

RESULTAT = evo1,

Name of the concept result which one wants to project.

Note:

For a evol_noli, the concept result will not contain (by defect [§3.7]) only the fields of
displacements. To calculate the internal variable and stress fields
correspondents, it is necessary to use command STAT_NON_LINE by using the key word
PREDICTION: “DEPL_CALCULE”.

3.5 Operand
MODELE_1

MODELE_1 = mo1,

Name of the model associated with the initial concept (evo1)

3.6 Operand
MODELE_2

MODELE_2 = mo2,

Name of the model associated with the concept result (resu). This model must be created as a preliminary.

3.7 Operand
CAS_FIGURE

This key word (optional) is used to direct the program towards one of the 4 following cases:

· “3D” Les only elements of the grid “1” which will be used for projection are the elements
voluminal: hexahedrons, pentahedrons, tetrahedrons and pyramids. The nodes have 3 cordonnées
(X, Y, Z).
· “2D” Les only elements of the grid “1” which will be used for projection are the elements
surface: quadrangles and triangles. The grid is supposed to be plane. The nodes have
2 cordonnées (X, Y).
· “2.5D” Les only elements of the grid “1” which will be used for projection are the elements
surface: quadrangles and triangles. The grid is 3D. The nodes have 3 cordonnées
(X, Y, Z). It is the case of the “hulls” plunged in 3D.
· “1.5D” Les only elements of the grid “1” which will be used for projection are the elements
linear: segments. The grid can be 2D or 3D. The nodes have 2 or 3 cordonnées
(X, Y, (Z)).

This key word can also be used under key word VIS_A_VIS. It can change value according to
occurrences.

If the user does not inform this key word, the program adopts following logic:
One traverses the list of the meshs of model 1 candidates to to be projected (this list can be filtered
thanks to key word VIS_A_VIS)

· if there exists at least 1 mesh 3D in this list
=> CAS=' 3d'
· if not:
­ if there exists at least 1 mesh 2D in this list
if the geometry is “2D”
=> CAS=' 2d'
if the geometry is “3D”
=> CAS='2.5D'
­ if not
:

­ if there exists at least 1 mesh 1D in this list => CAS='1.5D'

3.8
Selection of the names of the fields

The key words TOUT_CHAMP = “OUI” or NOM_CHAM = l_noch make it possible to choose which are them
fields of the SD RESULTAT which one wants to project (by defect all fields with the nodes). One can
also to project the fields by elements “ELNO” and “ELEM” (but not “ELGA”); for that, it is necessary
explicitly to give their names via key word NOM_CHAM.
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

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:
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3.8.1 Remarks on the projection of the fields by elements

This possibility was introduced initially to make it possible to project the fields of pressure
calculated by Code Saturne (constant by elements) on the skin of a mechanical grid Aster. It
development being general, it is available for all the fields “ELEM” and “ELNO” but sound
use can sometimes surprise the user.

As for the fields with the nodes, the fields by projected elements of the concept evo1 in
concept resu will bear the same names (for example: “SIGM_ELNO_DEPL”).
The projected fields (resu) will be by “natural” defect in the same way as the fields “origin” (evo1):
“ELEM” or “ELNO”.

One can however modify this behavior by defect by using key word TYPE_CHAM=' NOEU'
to force the fields projected to be fields with the nodes.

What does one make numerically?

· Fields of the type ELNO: for each mesh of grid 2, one traverses the nodes of this
net and the value of each node is calculated as one would do it for a field with the nodes.
The result of this projection is thus (by construction), a field ELNO which is continuous
between the elements.
· Fields of the type ELEM (constant by mesh): the value carried by a mesh of grid 2 is
obtained by arithmetic mean of the values carried by its nodes (calculated like
for a field ELNO).

When TYPE_CHAM=' NOEU' is not used, the projection of fields by elements only has direction
if the elements projected the ones on the others are in the same way “standard” (hull, beam, Iso
parametric). Indeed, if one projected for example a field 3D of “SIGM_ELNO_DEPL” on one
formed linear model of elements of bar, one could not store the values of constraints SIXX,
… on these elements (which know only the generalized efforts: NR, MX,…)

3.8.2 Operand
TYPE_CHAM= “NOEU”

This key word is used to force the fields projected to be fields “with the nodes”. This key word is used
systematically (for example) by command MACR_LIGN_COUPE because one cannot create
fields by elements on the “fictitious” model of beam created by this macro-command of
visualization.

3.9 Operand
DISTANCE_MAX

To project grid MA1 on grid MA2, method (ELEM) seeks in which element of
grid MA1 is each node of MA2, then interpolates the value using the functions of form
element. When that a node of MA2 is not in any element of grid MA1, the method puts
in relation the node etle not (of the edge) of the element nearest. It interpolates the value using
functions of form of the element and that even if the node is “far” from this element.
If it is wished that a node which is not in any the elements of grid MA1, not be concerned
by projection, one uses operand DISTANCE_MAX. Cet operand allows to give the distance
maximum that one authorizes between the node and the element nearest.
If the node does not answer the criterion of proximity the field will not be projected on this node (i.e it
node will not carry any component). By defect, an alarm will be emitted (see the key word
ALARME=OUI/NOT)

3.10 Operand
ALARME= “YES”/“NOT”

When a node of the grid “2” is found “far” from the elements of the grid “1” (see key word
DISTANCE_MAX above), the code transmits by defect a message of alarm. One can avoid these alarms
by using ALARME=' NON'.
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

Code_Aster ®
Version
8.2
Titrate:
Operator PROJ_CHAMP


Date:
31/01/06
Author (S):
J. Key PELLET
:
U4.72.05-F1 Page:
8/8

3.11 Operand
PROL_ZERO= “NOT”/“YES”

When the user wants to impose a classification on the fields of the SD_RESULTAT, it must use
one of key words RIGI_MECA, MASS_MECA or AMOR_MECA.
If desired classification imposes that a given node carries components and that the criterion of
DISTANCE_MAX makes that this node is not concerned with projection, one is unable to affect
values on this node. There will be, by defect, a fatal error in this case of figure. To avoid this
fatal error, the user must use word key PROL_ZERO=' OUI' in order to affect value 0. on it
node.

3.12 Operands
RIGI_MECA, MASS_MECA and AMOR_MECA

These 3 key words make it possible to associate (for a structure of data of the type “mode”) theirs
matr_asse with the structure of data produced. They are necessary if one wishes to use the result
command in later calculations (commands REST_BASE_PHYS, MACRO_PROJ_BASE,
…).

3.13 Selection of the sequence numbers

cf [U4.71.00].

3.14 Operand
SENSIBILITE

SENSIBILITE = will listpara,

This key word is followed of a sensitive parameter list. It specifies that one is not interested in
result in itself, but with derived from the result compared to the significant parameters.

3.15 Operand
TITER

TITER = titr,

Titrate that one wants to give to the concept result.

4 Example

Calculations thermics and mechanics on two different grids.

Note:

The mechanical model can contain (for example) elements of cable nonpresent in
the thermal model.

ma1=LIRE_MAILLAGE (...)
;
mo1=AFFE_MODELE (MAILLAGE=ma1,
AFFE=_F (TOUT=' OUI', PHENOMENE=' THERMIQUE',…));

evo1
= THER_LINEAIRE (MODEL = MO1,…);

ma2 = LIRE_MAILLAGE (...);
# grid more refined
MO2 = AFFE_MODELE (MAILLAGE= MA2,… “THERMAL”,…);

evo2
= PROJ_CHAMP (METHODE= “ELEM”, RESULTAT= EVO1, NOM_CHAM= “TEMP”,





MODELE_1= mo1, MODELE_2= mo2,
);

CH2 = AFFE_CHAR_MECA (TEMP_CALCULEE= EVO2,…
Handbook of Utilization
U4.7- booklet: Operations on the results and the fields
HT-62/06/004/A

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