Code_Aster
®
Version
7.4
Titrate:
Operator
POST_ZAC
Date:
31/01/05
Author (S):
S. TAHERI, J. ANGLES, Mr. BONNAMY
Key
:
U4.83.21-D
Page
:
1/6
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
Organization (S):
EDF-R & D/AMA, AUSY
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
Document: U4.83.21
Operator
POST_ZAC
1 Goal
To determine a state adapted or adapted by the method Zarka-Rack.
This operator gives within the framework of cyclic elastoplasticity with a model of work hardening
linear kinematics the adapted or adapted state of the structure under periodic loading
(presumedly elastic) refines or not refines, with or without calculation of an initial state (for example the first
cycle) elastoplastic. Moreover, it gives estimates of the variables of the amplitude type of stress
or plastic deformation, or their average values with the absolute limit saturated thanks to the method
simplified Zarka-Rack (ZAC). The method is not validated for the phenomenon of accommodation
in the case of a loading nonclosely connected.
The concept produced by this operator is of type
mult_elas
comprising one (adaptation) or three
(accommodation) sequence numbers equivalent to the values with the absolute limit (average, amplitude) and
containing the fields of solution displacements of the homogeneous elastic problems with
initial deformations [R7.06.01] as well as the amplitudes of stresses, plastic deformation and
an elementary indicator of adaptation or accommodation.
Product a concept of the mult_elas type.
Code_Aster
®
Version
7.4
Titrate:
Operator
POST_ZAC
Date:
31/01/05
Author (S):
S. TAHERI, J. ANGLES, Mr. BONNAMY
Key
:
U4.83.21-D
Page
:
2/6
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
2 Syntax
[mult_elas] = POST_ZAC
(
MODEL
=
Mo
,
[model]
CHAM_MATER
=
chmater,
[cham_mater]
EXCIT =_F (
CHARGE
=
chi
,
[char_meca]
FONC_MULT
=
fi
,
[function]
TYPE_CHARGE= “FIXE_CSTE”,
[DEFECT]
),
EVOL_ELAS
=
evol_elas
,
[evol_elas]
/
NUME_ORDRE =
l_nuor
,
[l_I]
/
LIST_INST
=
l_inst
,
[listr8]
/
INST =
inst,
[l_R]
TEMP_ZAC
=
/
temp,
[R]
/
0.
,
[DEFECT]
EVOL_NOLI
=
evol_noli
,
[evol_noli]
INST_MAX
=
inst,
[R]
|
PRECISION
=
/
prec,
[R]
/
1.0E-3
,
[DEFECT]
|
CRITERION =
/
“RELATIVE”
,
[DEFECT]
/
“ABSOLUTE”
,
)
Code_Aster
®
Version
7.4
Titrate:
Operator
POST_ZAC
Date:
31/01/05
Author (S):
S. TAHERI, J. ANGLES, Mr. BONNAMY
Key
:
U4.83.21-D
Page
:
3/6
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
3 Operands
3.1 Operands
MODEL
/
CHAM_MATER
MODEL = Mo
Name of the model whose elements are the subject of calculation.
CHAM_MATER = chmater
Field of affected material to the model
Mo
. One must find the characteristics material there
used during the elastic designs and elastoplastic preconditions to method ZAC.
3.2 Word
key
EXCIT
Cf [U4.51.03].
Two types of loading are taken into account here:
·
Boundary conditions kinematics of the problem (of imposed displacement type).
·
If the intermediate variable
0
(initial state for method ZAC) is calculated with
to start from an elastoplastic calculation, the operator
POST_ZAC
need has for calculation for
plastic deformation
(
)
p
T
E
HT
=
-
-
and of the field of temperature which was useful for it
calculation.
3.3 Operand
EVOL_ELAS
EVOL_ELAS = evol_elas
Name of a concept result of the type
evol_elas
.
The result of the type here is indicated
evol_elas
post-to treat and moments of elastic design
corresponding to the cycle of loading which one seeks the absolute limit by the simplified method
ZAC. Two moments are enough in the case of a loading refines (mini load and maximum loading).
structure of data must comprise the fields displacements with the nodes and stresses with
points of Gauss.
3.3.1 Operands
NUME_ORDRE/INST/LIST_INST
Cf [U4.71.00].
3.4 Operand
TEMP_ZAC
If the characteristics material depend on the temperature, this operand allows
to indicate the temperature to which one wants that the characteristics material are used in
method ZAC. The values are interpolated in the functions material contained in the field
given by the operand
CHAM_MATER
. The temperature is optional if the constants
material are independent of the temperature (constant temperature).
Code_Aster
®
Version
7.4
Titrate:
Operator
POST_ZAC
Date:
31/01/05
Author (S):
S. TAHERI, J. ANGLES, Mr. BONNAMY
Key
:
U4.83.21-D
Page
:
4/6
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
3.5 Operand
EVOL_NOLI
EVOL_NOLI = evol_noli
Name of a concept result of the type
evol_noli
.
One indicates here the results of the preliminary elastoplastic calculation of which one of the moments will use for
to determine the initial state within the meaning of method ZAC:
0
=
-
+
C
Ap
With
Ae
~
~
, where
~
With
is it
diverter of the stresses (obtained by elastoplastic calculation) and
~
With
E
the diverter of the stresses
for this same calculation carried out in elasticity. The moment of elastic design are equivalent must be present
in the structure of data indicated by the key word
EVOL_ELAS
. The structure of data must
to comprise the fields displacements with the nodes and stresses at the points of Gauss. If this
operand is not indicated, then the initial state within the meaning of method ZAC is null:
0
0
=
.
3.5.1 Operand
INST_MAX
INST_MAX = inst
[R]
One indicates here the moment tmax (maximum loading before discharge) of elastoplastic calculation (word
key
EVOL_NOLI
) which will use to determine the initial state. This moment must also be present in
the list of moments provided with the key word
EVOL_ELAS
.
3.6 Operands
PRECISION
/
CRITERION
Cf [U4.71.00]. These operands are to be used with the operand
INST_MAX
and allow to refine
the extraction of a field by a real variable of access. By defect PRECISION = 1.D-3 and
CRITERION = “RELATIVE”.
4
Results provided in the produced concept
The produced concept is of type
mult_elas
and comprises is a sequence number (situation
of adaptation), that is to say three sequence numbers (situation of accommodation).
Those are referred by the variable of access
NOM_CAS
. This variable of access is worth is:
“AVERAGE VALUE”, either “AMPLITUDE I”, or “AMPLITUDE S”.
The following fields are stored:
|
“DEPL”
Displacements obtained by the resolution of the homogeneous elastic problems fitted with
initial deformation (
lim
or
moy
I
S
,
,
).
|
“SIEF_ELGA”
Stress field at the points of Gauss calculated starting from preceding displacements. It
represent the state of residual stresses estimated by method ZAC.
|
“ALPH0_ELGA_EPSP”
Initial State
()
0
calculated at the points of Gauss starting from the data of elastoplastic calculation,
cf [§3.5],
(
~
~)
0
=
-
+
C
Ap
Ap
Ae
if the aforementioned is indicated if not the initial state is null
(
)
0
0
=
.
Code_Aster
®
Version
7.4
Titrate:
Operator
POST_ZAC
Date:
31/01/05
Author (S):
S. TAHERI, J. ANGLES, Mr. BONNAMY
Key
:
U4.83.21-D
Page
:
5/6
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
|
“ALPHP_ELGA_ALPHP”
Fields (
lim
or
moy
I
S
,
,
) calculated at the points of Gauss starting from the projection of
the initial state
()
0
on the intersection of convex of center
~
iel
and of radius
y
,
y
threshold of
plasticity and
I
index of loading.
|
“SIGM_ELNO_ZAC”
Mean stresses and two amplitudes of stresses to the nodes with the absolute limit:
lim
(residual stress) for the sequence number 1 in a case of adaptation,
moy
,
I
,
S
for the sequence numbers 1,2 and 3 in a case of accommodation.
|
“EPSP_ELNO_ZAC”
Average plastic deformations and amplitudes of deformations to the nodes with the absolute limit:
lim
p
for the sequence number 1 in a case of adaptation,
moy
p
,
I
p
,
S
p
for the sequence numbers 1,2 and 3 in a case of accommodation.
|
“VARI_ELGA_ZAC”
Elementary indicator on the nature of the phenomenon to the absolute limit. Value 1 indicates one
situation of accommodation and the value a 0 situation of adaptation on the element considered.
This field is stored on the sequence number 1 only.
Caution:
·
The file result comprises a message specifying the situation with the absolute limit
(ADAPTATION or ACCOMMODATION).
·
A situation of accommodation in the case of a loading nonclosely connected causes one
and emission program stop of a message in the file RESULT: method
is then not applicable.
Code_Aster
®
Version
7.4
Titrate:
Operator
POST_ZAC
Date:
31/01/05
Author (S):
S. TAHERI, J. ANGLES, Mr. BONNAMY
Key
:
U4.83.21-D
Page
:
6/6
Instruction manual
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A
5 Examples
5.1
Calculation without initial state
solsta = MECA_STATIQUE (
MODEL = Mo,
LIST_INST = listel,
CHAM_MATER = chmat,
EXCIT = _F (LOAD = chme),
OPTION = (“SIEF_ELGA_DEPL”, “EPSI_ELGA_DEPL”)
)
chzac1 = POST_ZAC (MODEL = Mo, CHAM_MATER = chmat,
EXCIT = _F (LOAD = chme),
EVOL_ELAS = solsta, LIST_INST = listel)
)
5.2
Calculation with initial state
solpl = STAT_NON_LINE (
MODEL = Mo,
CHAM_MATER = chmat,
EXCIT = _F (LOAD = chpres, FONC_MULT = varpress),
EXCIT = _F (LOAD = chcl),
COMP_INCR = _F (RELATION = “VMIS_CINE_LINE”),
INCREMENT = _F (LIST_INST = listpl, NUME_INST_FIN = 20),
NEWTON = _F (MATRIX = “TANGENT”),
CONVERGENCE = _F (RESI_GLOB_RELA= 0.001,
ITER_GLOB_MAXI= 100)
)
solsta = MECA_STATIQUE = (
MODEL = Mo,
LIST_INST = listel,
CHAM_MATER = chmat,
EXCIT = _F (LOAD = chme),
OPTION = (“SIEF_ELGA_DEPL”, “EPSI_ELGA_DEPL”)
)
chzac2 = POST_ZAC (MODEL = Mo, CHAM_MATER = chmat,
EXCIT
=
_F (
CHARGE
=
chme
),
EVOL_ELAS = solsta, LIST_INST = listel
EVOL_NOLI = solpl, INST_MAX = 3.
)