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Code_Aster
®
Version
7.4
Titrate:
Operator
MODE_ITER_CYCL
Date:
08/03/05
Author (S):
O. NICOLAS, E. BOYERE
Key
:
U4.52.05-G
Page
:
1/6
Instruction manual
U4.5- booklet: Methods of resolution
HT-66/05/004/A
Organization (S):
EDF-R & D/AMA














Instruction manual
U4.5- booklet: Methods of resolution
Document: U4.52.05



Operator
MODE_ITER_CYCL








1 Goal
To calculate the clean modes of a structure with cyclic symmetry.
One calculates the generalized components of the clean modes of the whole structure, by a method
of cyclic under-structuring, starting from the modal base of a sector of reference. The axis of symmetry
is axis OZ. The modal base of sector must be of the CONVENTIONAL type. The interfaces STRAIGHT LINE,
LEFT and possibly AXIS must be in the same way standard. The sides right and left are defined by
the trigonometrical direction in plan OXY.
Product a structure of data of the mode_cycl type.
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Code_Aster
®
Version
7.4
Titrate:
Operator
MODE_ITER_CYCL
Date:
08/03/05
Author (S):
O. NICOLAS, E. BOYERE
Key
:
U4.52.05-G
Page
:
2/6
Instruction manual
U4.5- booklet: Methods of resolution
HT-66/05/004/A
2 Syntax

mocy [mode_cycl] = MODE_ITER_CYCL
(
BASE_MODALE
=
bamo,
[base_modale]
NB_MODE =
/
nbmo,
[I]
/
999
,
[DEFECT]
NB_SECTEUR
=
nbsec,
[I]
CONNECTION = _F
(
STRAIGHT LINE
=
“nom_int”,
[KN]
LEFT
=
“nom_int”,
[KN]
CENTER
=
“nom_int”, [kN]
),
CALCULATION = _F
(
TOUT_DIAM
=/“YES”,
NB_DIAM = Li,
[l_I]
OPTION =/“PLUS_PETITE”,
[DEFECT]
/
“CENTER”,
/
“TAPE”,
FREQ = lifreq,
[l_R]
NMAX_FREQ =/nbfreq,
[I]
/
10,
[DEFECT]
PREC_SEPARE =
/
pre_sep,
[R]
/
1.E+2,
[DEFECT]
PREC_AJUSTE =
/
pre_ajus,
[R]
/
1.E-6,
[DEFECT]
NMAX_ITER
=
/
niter,
[I]
/
50,
[DEFECT]
),
VERI_CYCL = _F
(
PRECISION
=
/
prec, [R]
/
1.D-3,
[DEFECT]
CRITERION =
/
“RELATIVE”, [DEFECT]
DIST_REFE =
dist_ref, [R]
),
INFORMATION =
/
1,
[DEFECT]
/
2,

)
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Code_Aster
®
Version
7.4
Titrate:
Operator
MODE_ITER_CYCL
Date:
08/03/05
Author (S):
O. NICOLAS, E. BOYERE
Key
:
U4.52.05-G
Page
:
3/6
Instruction manual
U4.5- booklet: Methods of resolution
HT-66/05/004/A
3 Operands
3.1 Operand
BASE_MODALE
BASE_MODALE = bamo
Name of the modal base of the sector built by
DEFI_BASE_MODALE
[U4.64.02].
3.2 Operand
NB_MODE
NB_MODE = nbmo
A number of modes clean of the sector to be used for cyclic calculation. By defect, if the key word
does not appear, all the clean modes of the modal base are used.
3.3 Operand
NB_SECTEUR
NB_SECTEUR = nbsec
A number of basic sectors necessary to the construction of the total structure.
3.4 Word
key
CONNECTION
CONNECTION
Key word factor for the definition of the connections between the sectors.
3.4.1 Operands
STRAIGHT LINE
/
LEFT
/
CENTER
See [Figure 3.6-a].
STRAIGHT LINE = “nom_int”
Name of the right interface of the sector.
LEFT = “nom_int”
Name of the left interface of the sector.
CENTER = “nom_int”
Name of the interface of the axis of the sector.
They are points common to all the sectors.
3.5 Word
key
CALCULATION
CALCULATION
Key word factor to define it mode of search of the clean modes.
3.5.1 Operands
TOUT_DIAM
/
NB_DIAM
TOUT_DIAM = “YES”
The modes associated with all the numbers of nodal diameters will be calculated.
NB_DIAM = Li
List numbers of nodal diameters to calculate. By defect, all the numbers of
possible nodal diameters are studied.
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Code_Aster
®
Version
7.4
Titrate:
Operator
MODE_ITER_CYCL
Date:
08/03/05
Author (S):
O. NICOLAS, E. BOYERE
Key
:
U4.52.05-G
Page
:
4/6
Instruction manual
U4.5- booklet: Methods of resolution
HT-66/05/004/A
3.5.2 Operand
OPTION
OPTION =
“PLUS_PETITE”
: to calculate by a method of iteration reverses the clean modes
corresponding to the smallest frequencies for each number of
diameters requested.
“CENTER”
:
to calculate the clean modes centered around a frequency requested
by the key word
LIST_FREQ
.
“TAPE”
:
to calculate the clean modes between two frequencies given by
the user by the key word
LIST_FREQ
.
The Eigen frequencies are separated by dichotomy then the modes
clean calculated by iterations opposite centered on the frequencies
exits of the stage of separation.
3.5.3 Operands
FREQ
/
NMAX_FREQ
FREQ = lifreq
List frequencies of which the use depends on the selected option:
OPTION
=
“TAPE”
2 values are awaited
(
)
F
F
1
2
who define the tape.
OPTION
=
“CENTER”
1 is awaited value which is the center frequency of the interval.
OPTION
=
“PLUS_PETITE”
One calculates the smallest Eigen frequencies of the structure. By defect, one calculates them
10 first. Key word FREQ then does not have a direction in this case, it does not have to be
informed.
NMAX_FREQ = nbfreq
A number of frequencies to be calculated for each number of nodal diameters asked. If it
key word does not appear, one calculates as many frequencies, for each nodal diameter, that there is
clean modes used in the modal base (key word
NB_MODE
).
3.5.4 Operands
PREC_SEPARE
/
PREC_AJUSTE
/
NMAX_ITER
PREC_SEPARE = pre_sep
Precision of separation of the frequencies for option
“TAPE”
.
PREC_AJUSTE = pre_ajus
Precision used for the calculation of the modes (all
OPTIONS
).
NMAX_ITER = niter
Numbers maximum iterations opposite (all
OPTIONS
).
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Code_Aster
®
Version
7.4
Titrate:
Operator
MODE_ITER_CYCL
Date:
08/03/05
Author (S):
O. NICOLAS, E. BOYERE
Key
:
U4.52.05-G
Page
:
5/6
Instruction manual
U4.5- booklet: Methods of resolution
HT-66/05/004/A
3.6 Word
key
VERI_CYCL
VERI_CYCL
Key word for checking of the coherence of the interfaces given in cyclic term of repetitivity.

Interface left
Interface right
Interface axis
Z
X
Y
Appear 3.6-a

3.6.1 Operands
PRECISION/DIST_REFE
PRECISION = prec
DIST_REFE = dist_ref
The test of coherence between 2 contiguous sectors will be determined by the product prec * dist_réf. If
DIST_REFE is not indicated, it will be automatically calculated proportionally with prec and with
a maximum value of co-ordinate of a sector.

3.7 Operand
INFORMATION
INFORMATION =
Level of impression
1
no impression,
2
writing of the frequencies and generalized parameters obtained and the participations
relative of the various modes of the base.
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Code_Aster
®
Version
7.4
Titrate:
Operator
MODE_ITER_CYCL
Date:
08/03/05
Author (S):
O. NICOLAS, E. BOYERE
Key
:
U4.52.05-G
Page
:
6/6
Instruction manual
U4.5- booklet: Methods of resolution
HT-66/05/004/A
4
Cyclic under-structuring example
ANNULAR PLATE ENCASTREE ON A HUB - METHOD OF CRAIG-BAMPTON
sector =
LIRE_MAILLAGE
(
)
model =
AFFE_MODELE
(
MAILLAGE=
sector,
AFFE
=_F (ALL = ' OUI',
PHENOMENON = ' MECANIQUE',
MODELISATION=' DKT')
)
to subdue =
DEFI_MATERIAU
(ELAS =_F (E=2.E11, NU=0.3, RHO=7800.0)
)
chammat =
AFFE_MATERIAU
(MAILLAGE= sector,
AFFE =_F (ALL = ' OUI', MATER= MATER)
)
chamcar =
AFFE_CARA_ELEM (MODEL = model,
HULL = (ALL = ' OUI', EPAIS= 0.001)
)
charge =
AFFE_CHAR_MECA (MODEL = model
DDL_IMPO= (TOUT=' OUI', DX=0., DY=0., DRZ=0.),
DDL_IMPO= (GROUP_NO=' AXE', DZ=0., DRX=0., DRY=0.),
DDL_IMPO= (GROUP_NO=' DROIT', DZ=0., DRX=0., DRY=0.),
DDL_IMPO= (GROUP_NO=' GAUCH', DZ=0., DRX=0., DRY=0.))
#
#
CONSTRUCTION OF THE MATRICES OF RIGIDITY AND MASS OF THE BASIC SECTOR
#
rigiele =
CALC_MATR_ELEM (MODEL = model, LOAD = load,
CHAM_MATER= chammat, CARA_ELEM = chamcar,
OPTION =
“RIGI_MECA”
)
massele =
CALC_MATR_ELEM (MODEL = model,
CHARGE = load,
CHAM_MATER= chammat, CARA_ELEM = chamcar,
OPTION =
“MASS_MECA”)
numerot =
NUME_DDL
(MATR_RIGI
=
rigiele)
matrigi =
ASSE_MATRICE
(MATR_ELEM = rigiele, NUME_DDL = numerot
)
matmass =
ASSE_MATRICE
(MATR_ELEM = massele, NUME_DDL = numerot
)
#
#
CALCULATION OF THE DYNAMIC MODES OF THE BASIC SECTOR
#
modes =
MODE_ITER_SIMULT
(MATR_A = matrigi, MATR_B = matmass,
CALC_FREQ= _F (NMAX_FREQ= 15)
)
#
#
DEFINITION OF THE INTERFACES AND THE STATIC MODES ASSOCIATE
#
lint =
DEFI_INTERF_DYNA
(NUME_DDL = numerot, IMPR= 2,
INTERFACE= _F (NOM=' DROITE', TYPE=' CRAIGB',
GROUP_NO=
“RIGHT”,
MASQUE= (“DX”, “DY”, “DRZ”),),
INTERFACE= _F (NOM=' GAUCHE', TYPE=' CRAIGB',
GROUP_NO=
“GAUCH”,
MASQUE= (“DX”, “DY”, “DRZ”)))
#
#
CALCULATION OF THE BASE OF PROJECTION = RECOVERY OF THE DYNAMIC MODES
# AND CALCULATION OF THE STATIC MODES
bamo =
DEFI_BASE_MODALE
(CLASSIQUE= _F (INTERF_DYNA= lint, IMPR= 2,
MODE_MECA = modes,
NMAX_MODE=
15
)
)
#
#
CALCULATION
MODES
CYCLIC
#
modcyc =
MODE_ITER_CYCL (BASE_MODALE= bamo, NB_MODE=15, NB_SECTEUR=18,
LIAISON=_F (“RIGHT” DROITE=,
“LEFT” GAUCHE=),
CALCULATION =_F (NB_DIAM= (0, 1, 2, 3), NMAX_FREQ=2))