background image
Code_Aster
®
Version
7.4
Titrate:
Operator
COMB_FOURIER
Date:
04/01/05
Author (S):
X. DESROCHES
Key
:
U4.83.31-E
Page
:
1/4
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
Organization (S):
EDF-R & D/AMA














Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
Document: U4.83.31



Operator
COMB_FOURIER








1 Goal
To recombine the modes of FOURIER of a structure of data result in directions
particular. The modes are produced for a model
“AXIS_FOURIER”
by the macro control
MACRO_ELAS_MULT
[U4.51.02].
This is possible for displacements, the reactions, the fields of strains and stresses
in elasticity.
The structure of data produced is of type
comb_fourier
.
background image
Code_Aster
®
Version
7.4
Titrate:
Operator
COMB_FOURIER
Date:
04/01/05
Author (S):
X. DESROCHES
Key
:
U4.83.31-E
Page
:
2/4
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
2 Syntax

comb [comb_fourier] = COMB_FOURIER
(
RESULT
=
resu,
[fourier_elas]
NOM_CHAM =
|
“DEPL”
|
“REAC_NODA”
|
“SIEF_ELGA_DEPL”
|
“EPSI_ELNO_DEPL”
|
“SIGM_ELNO_DEPL”
,
ENG =
langl,
[l_R]
)
background image
Code_Aster
®
Version
7.4
Titrate:
Operator
COMB_FOURIER
Date:
04/01/05
Author (S):
X. DESROCHES
Key
:
U4.83.31-E
Page
:
3/4
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
3 Operands
Recall:
The recombination of FOURIER on displacements is written:

()
U
U
U
=
-




+














=
cos
cos
sin
sin
sin
cos
L
L
L
With
L
L
L
With
S
L
S
has
L
has
L
NR
0
0
0
0
0
1
2
4444
3
4444
1
2
4444
3
4444

A symmetrical harmonic is thus recombined with the matrix
With
S
, a harmonic
antisymmetric with the matrix
With
has
.
The recombination of FOURIER on the strains and the stresses is written:

()
=
-




+






=
cos
sin
sin
cos
,
,
,
,
L I
L I
L I
L I
L
S
L
has
L
NR
4
4 2
2 4
2
4
4 2
2 4
2
0
0
0
0
0

3.1 Operand
RESULT
RESULT = resu,
Name of the concept of the type
fourier_elas
from which one will recombine the modes.

3.2 Operand
NOM_CHAM
NOM_CHAM = nomsymb,
Reference symbol of the recombined fields.

3.3 Operand
ENG
ENG = langl,
Angle (S) in degrees of (or of) the section (S) where the recombination of FOURIER takes place.
background image
Code_Aster
®
Version
7.4
Titrate:
Operator
COMB_FOURIER
Date:
04/01/05
Author (S):
X. DESROCHES
Key
:
U4.83.31-E
Page
:
4/4
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
4 Example
The example below carries out a calculation on 2 harmonics of Fourier by
MACRO_ELAS_MULT
,
enriches the concept of the type
RESULT
by
CALC_NO
before recombining the computed fields by
COMB_FOURIER
.
BEGINNING ()
m = LIRE_MAILLAGE ()
Mo = AFFE_MODELE (MESH = m,
AFFE = _F (ALL = “YES”,
PHENOMENON = “MECHANICAL”,
MODELISATION= “axis_fourier”))
my = DEFI_MATERIAU (ELAS = _F (E = 72.,
NAKED = 0.3,
RHO = 0.,))
cm = AFFE_MATERIAU (MESH = m,
AFFE = _F (ALL = “YES”,
MATER = my,))
bloqu = AFFE_CHAR_MECA_F (MODEL = Mo,
DDL_IMPO = _F (NODE = “N1”, DX = 0., DY = 0., DZ = 0. ),
(NODE = “N2”, DY = 0.,),
(NODE = “N3”, DY = 0.,),)
CH = AFFE_CHAR_MECA (MODEL = Mo,
PRES_REP = _F (GROUP_MA = “end”, PRES= 100.,),)
#
# FOURIER CALCULATION ON THE 2 FIRST SYMMETRICAL HARMONICS
#
resu = MACRO_ELAS_MULT (MODEL = Mo,
CHAM_MATER = cm,
CHAR_MECA_GLOBAL= bloqu,
CAS_CHARGE= (
_F (MODE_FOURIER = 1,
TYPE_MODE = “SYME”,
CHAR_MECA = CH,
OPTION = “SIGM_ELNO_DEPL”,
SOUS_TITER = “mode Fourier 1 SYME”),
_F (MODE_FOURIER = 2,
TYPE_MODE = “SYME”,
CHAR_MECA = CH,
OPTION = “SIGM_ELNO_DEPL”,
SOUS_TITER = “Fourier mode 2 SYME”),),
)
#
# CALCULATION OF THE NODAL REACTIONS BY CALC_NO
#
resu = CALC_NO (reuse = resu,
RESULT = resu,
OPTION = “REAC_NODA”,
angl1 = 45.
angl2 = 135.
#
# RECOMBINATION OF FOURIER ON DISPLACEMENTS, REACTIONS AND FORCED
FOR 45° AND 135°
#
co_four = COMB_FOURIER (RESULT = resu,
NOM_CHAM = (“DEPL”, “REAC_NODA”,
“SIGM_ELNO_DEPL”),
ENG = (angl1, angl2),
)
END ()