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

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

Handbook of Utilization
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 command
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 comb_fourier type.
Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A

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

2 Syntax
comb [comb_fourier] = COMB_FOURIER
(







RESULTAT
=
resu,
[fourier_elas]






NOM_CHAM = | “DEPL”











| “REAC_NODA”











| “SIEF_ELGA_DEPL”











| “EPSI_ELNO_DEPL”











| “SIGM_ELNO_DEPL”
,







ANGL =
langl,
[l_R]











)
Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A

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

3 Operands

Recall:

The recombination of FOURIER on displacements is written:






cosl

sinl
0
NR
0






U () =

cosl
custom +
has
L

sin L
U

L
L = 0

0
- sinl

0
cosl

1
2
4444
3
4444
1444 2
4
3
4444


Have
Aa


A symmetrical harmonic is thus recombined with the matrix Have, a harmonic
antisymmetric with the Aa matrix.

The recombination of FOURIER on the strains and the stresses is written:

NR
L I4
04,2
sin
L I4
04,2

() =

cos

S +
has
L


0
sin L I
0
cosl I
L

L =
-



2,4
2

2,4
2
0



3.1 Operand
RESULTAT

RESULTAT = resu,

Name of the concept of the fourier_elas type from which one will recombine the modes.

3.2 Operand
NOM_CHAM

NOM_CHAM = nomsymb,

Reference symbol of the recombined fields.

3.3 Operand
ANGL

ANGL = langl,

Angle (S) in degrees of (or of) the section (S) where the recombination of FOURIER takes place.
Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A

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

4 Example

The example below carries out a calculation on 2 harmonics of Fourier by MACRO_ELAS_MULT,
enriches the concept of the type RESULTAT by CALC_NO before recombining the computed fields by
COMB_FOURIER.

DEBUT ()
m = LIRE_MAILLAGE ()
Mo = AFFE_MODELE (MAILLAGE = 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 (MAILLAGE = m,
AFFE = _F (ALL = “YES”,
MATER = my,))
bloqu = AFFE_CHAR_MECA_F (MODELE = Mo,
DDL_IMPO = _F (NODE = “N1”, DX = 0., DY = 0., DZ = 0. ),
(NODE = “N2”, DY = 0.,),
(NODE = “N3”, DY = 0.,),)
CH = AFFE_CHAR_MECA (MODELE = Mo,
PRES_REP = _F (GROUP_MA = “end”, PRES= 100.,),)
#
# FOURIER CALCULATION ON THE 2 FIRST SYMMETRICAL HARMONICS
#
resu = MACRO_ELAS_MULT (MODELE = 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,
RESULTAT = resu,
OPTION = “REAC_NODA”,
angl1 = 45.
angl2 = 135.
#
# RECOMBINATION OF FOURIER ON DISPLACEMENTS, REACTIONS AND FORCED
FOR 45° AND 135°
#
co_four = COMB_FOURIER (RESULTAT = resu,
NOM_CHAM = (“DEPL”, “REAC_NODA”,
“SIGM_ELNO_DEPL”),
ANGL = (angl1, angl2),
)
FIN ()

Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A

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