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Code_Aster
®
Version
8.2
Titrate:
Operator
AFFE_MATERIAU
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.43.03-I1
Page
:
1/6
Instruction manual
U4.4- booklet: Modeling
HT-62/06/004/A
Organization (S):
EDF-R & D/AMA














Instruction manual
U4.4- booklet: Modeling
Document: U4.43.03



Operator
AFFE_MATERIAU








1 Goal
To assign materials to geometrical areas of a mesh.
Product a structure of data of the cham_mater. type.
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Code_Aster
®
Version
8.2
Titrate:
Operator
AFFE_MATERIAU
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.43.03-I1
Page
:
2/6
Instruction manual
U4.4- booklet: Modeling
HT-62/06/004/A
2 Syntax

chm [cham_mater] = AFFE_MATERIAU
(
MESH = my
,
/
[mesh]
/
[skeleton]
MODEL = Mo
,
[model]

# assignment of the name of material and the temperature of reference:
AFFE
=
(_F (
/ALL =
“YES”,
/
NET
= lma
,
[l_maille]
/
GROUP_MA
= lgma
,
[l_gr_maille]
MATER
=/chechmate
,
[to subdue]
/
l_mat,
[l_mater]
TEMP_REF
=/0.
, [DEFECT]
/
tref,
[R]

SECH_REF = sref,
[R]
),),

# assignment of the variables of controls:
AFFE_VARC
= (_F (
/ALL =
“YES”, [DEFECT]
/
|
NET
= lma
, [l_maille]
|
GROUP_MA
= lgma,
[l_gr_maille]
NOM_VARC
=/“IRRA”,
/
“CORR”,
/
“NEUT1”,
/
“NEUT2”,
/
CHAMP_GD = chvarc
[field]
/
EVOL
= evovarc [evol_sdaster]
NOM_CHAM = nosymb, [TXM]
VALE_REF = vref, [R]
),),
)
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Code_Aster
®
Version
8.2
Titrate:
Operator
AFFE_MATERIAU
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.43.03-I1
Page
:
3/6
Instruction manual
U4.4- booklet: Modeling
HT-62/06/004/A
3 General information
This control is used to affect the material characteristics on the finite elements of the model
(even if in fact the meshs of the mesh are really affected). These characteristics
material are defined by the materials which one affects on the meshs (key word MATER). Each
material contains a certain number of parameters (Young modulus, density,…). These
parameters can be related to certain variables. We will call these variables of
“variable of control”.
Currently, the variables of control used (in mechanics) are the temperature, the hydration,
drying, phases metallurgical, irradiation, corrosion,… But only affected variables
via control AFFE_MATERIAU for the moment the irradiation (IRRA) and corrosion (CORR) are.

4 Operands
4.1
MESH
MESH = my,
Name of the mesh (or the skeleton) which one wants to affect by material characteristics.
Note:
The operation of assignment is the same one for the meshs of a skeleton as for the meshs of one
mesh. In the continuation of the document, one will always say mesh to simplify.
When one affects materials on the meshs of a skeleton, it is that one wants to calculate
stresses (for example) on the meshs of postprocessing (coarser).

4.2 Place
of assignment
AFFE
Key word factor which makes it possible to affect various materials on “pieces” of the mesh.
/ALL = “YES”,
This key word makes it possible to affect on all the meshs of the mesh.
/GROUP_MA = lgma,
This key word makes it possible to affect on a list of groups of meshs of the mesh.
/
NET
=
lma,
This key word makes it possible to affect on a list of meshs of the mesh.
With each group of meshs, (key word
GROUP_MA
) or each list of meshs (key word
NET
),
or with all the mesh (key word
ALL
) a material is affected
chechmate
, which is a concept
product by one of the operators
DEFI_MATERIAU
[U4.43.01] or
DEFI_COQU_MULT
[U4.42.03].
Let us recall that the control
DEFI_MATERIAU
[U4.43.01] allows to define the parameters of
relations of behavior to be used for a mechanical, thermal, acoustic analysis.
order
DEFI_COQU_MULT
[U4.42.03] allows to define a homogenized material
representative of a laminated material multi-layer.
If a mesh appears explicitly (or implicitly) in several occurrences of the key word
factor
AFFE
, the rule of overload is observed: it is the last assignment which precedes
[U2.01.08].
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Code_Aster
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Version
8.2
Titrate:
Operator
AFFE_MATERIAU
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.43.03-I1
Page
:
4/6
Instruction manual
U4.4- booklet: Modeling
HT-62/06/004/A
4.3
Quantities to be affected
4.3.1 Notice concerning calculations of breaking process
In general, the material characteristics must be known finite elements modelizing
“matter”: “voluminal” elements (or of structure). The finite elements of “skin” are there for
to apply boundary conditions and do not have to know the material properties of the matter
subjacent. An exception exists for the calculation of option CALC_K_G of the operators
. For these calculations, the finite elements modelizing the lips of the fissure must be
affected by same material as the “voluminal” elements subjacent.
4.3.2 Operand
MATER
MATER = chechmate,
Name of the material which one wants to affect.
In the general case, each mesh is affected only by one material. Sometimes, it is necessary
to indicate a material list when the nonlinear mechanical behavior is obtained by
order DEFI_COMPOR [U4.43.06].
4.3.3 Operand
TEMP_REF
TEMP_REF = Tref,
The temperature of reference
T
ref.
introduced behind the key word
TEMP_REF
is the temperature for
which it does not have there thermal deformation (cf [R4.08.01]).
If the thermal expansion factor
(whose value is introduced into the control
DEFI_MATERIAU
[U4.43.01]) does not depend on the temperature:
()
(
)
HT
ref.
T
T T
=
-
.
If the thermal expansion factor depends on the temperature the mathematical expression
allowing the calculation of the thermal deformation differs according to the specification from
thermal expansion factor in the control
DEFI_MATERIAU
:
·
values of the thermal expansion factor (introduced into
DEFI_MATERIAU
) have
summer determined by tests of dilatometry carried out at the temperature
T
ref.
.
In this case, the key word
TEMP_DEF_ALPHA
does not have to be specified in the control
DEFI_MATERIAU
and the thermal deformation is calculated by the expression:
()
()
(
)
()
HT
ref.
HT
ref.
T
T
T T
T
=
-
=
and
0
where
()
T
is well informed under the key word
ALPHA
(or
ALPHA_ *
) in
DEFI_MATERIAU
.
·
the values of the thermal expansion factor are determined by tests of
dilatometry which took place at a temperature
T
def
different from the temperature from
reference
T
ref.
.
It is then necessary to carry out a change of reference mark in the calculation of the deformation
thermics [R4.08.01].
()
()
()
HT
m
HT
m
HT
ref.
T
T
T
=
-
where
m
HT
is the thermal deformation measured (definite compared to the temperature
T
def
),
HT
is the thermal deformation calculated (definite compared to the temperature
T
ref.
).
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Code_Aster
®
Version
8.2
Titrate:
Operator
AFFE_MATERIAU
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.43.03-I1
Page
:
5/6
Instruction manual
U4.4- booklet: Modeling
HT-62/06/004/A
The temperature
T
def
is well informed under the key word
TEMP_DEF_ALPHA
in
DEFI_MATERIAU
, and values of the expansion factor (definite compared to
temperature
T
def
) are well informed under the key word
ALPHA
or (
ALPHA_ *
) in
DEFI_MATERIAU
.
4.3.4 Operand
SECH_REF
SECH_REF: c0
[R]
c0 represents the water content initial of the concrete. The user must provide this number when it does one
mechanical calculation (MECA_STATIQUE or STAT_NON_LINE) with a loading of the type
SECH_CALCULEE.
c0 must be given in the same units as the “drying” of SECH_CALCULEE (for example in
L/m
3
). This unit must be coherent with parameter DEFI_MATERIAU/ELAS_FO/K_DESSIC.
With this water content initial, the withdrawal of desiccation is null since:
EPS_rd = K_DESSIC (C0-C).
4.4 Word
key
AFFE_VARC
This key word factor makes it possible to affect fields of variables of control on the meshs of
mesh. An occurrence of the key word is used to affect a variable of control. For the moment, both
variables of control usable in this control (IRRA and CORR) have each one only one
component (IRRA and COOR) but it is envisaged for example that a defomation (6 components EPXX,
EPYY,…) can be a variable of control.
4.4.1 Operand
NOM_VARC
NOM_VARC = nomvarc,
Name of the variable of control which one wants to affect (IRRA or CORR).
4.4.2 Operands
TOUT=' OUI', GROUP_MA=lgma, MAILLE=lmail
These key words make it possible to indicate the area to be affected.
4.4.3 Operand
CHAMP_GD=chvarc
This key word makes it possible to associate the variable of control nomvarc the field chvarc. This field is
a field of realities (not of functions). It is thus independent of time and will be used throughout
transitory calculations.
If the values of the variable of control are dependant on time, it is necessary to use key word EVOL
(see below).
In the field chvarc, the program will seek a of the same component name than nomvarc.
4.4.4 Operands
EVOL=evovarc and NOM_CHAM=nomsym
These key words make it possible to associate the variable of control nomvarc the transient evovarc.
key word NOM_CHAM makes it possible to indicate the reference symbol of the fields of SD_résultat to be used.
By defect, the code chooses NOM_CHAM=' IRRA' for NOM_VARC=' IRRA' and NOM_CHAM=' CORR' for
NOM_VARC=' CORR'. The fields are fields of realities (not functions). In these fields, it
program will seek a of the same component name than nomvarc.
4.4.5 Operand
VALE_REF=vref
This key word makes it possible to define a value of “reference” for the variable of control nomvarc. By
example, when drying is treated like a variable of control in the key word
AFFE_VARC, key word VALE_REF will replace key word current SECH_RÉF. the 2 current variables
(IRRA and CORR) do not have a value of reference.
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Code_Aster
®
Version
8.2
Titrate:
Operator
AFFE_MATERIAU
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.43.03-I1
Page
:
6/6
Instruction manual
U4.4- booklet: Modeling
HT-62/06/004/A
5 Examples
Example 1
chmat = AFFE_MATERIAU (MESH = my, AFFE = (
_F (ALL = “YES”, MATER = steel),
_F (MAILLE= (“ma1”, “ma2”, “ma3”), MATER=alu,
TEMP_REF=20.),),
)
On the whole of the mesh (except the meshs:
ma1
,
ma2
,
ma3
) the material of name is affected
steel
with the temperature of reference per defect: 0.
On the meshs
ma1
,
ma2
,
ma3
the material is affected
aluminum
with the temperature of reference 20.

Example 2
Assignment on all the mesh of the material CHECHMATE whose certain parameters are related to
irradiation. The temporal evolution of the irradiation is given via the SD result EVOL = FLUENC.
CHMAT = AFFE_MATERIAU (MESH = MA,
AFFE =_F (TOUT=' OUI', MATER = CHECHMATE,),
AFFE_VARC=_F (NOM_VARC=' IRRA', EVOL =FLUENC,),
)

Example 3
Use of the variable of control “NEUT1” to simulate a dependence of the coefficients
hardware according to the Young modulus.
In this example (resulting from the case test ssnv130c), one wants to illustrate the possibility of using a field of
Young modulus whom one supposes known (CHYOUNG). For example, this field is read in a file
(LIRE_CHAMP) or it is the result of a calculation. One then will define a material for which
Young modulus (key word E) is the function “identity” of variable “NEUT1” and the field is affected
CHYOUNG like variable of control “NEUT1”.
CHYOUNG=…
NU_F=DEFI_CONSTANTE (VALE=0.3)
E_F = DEFI_FONCTION (NOM_PARA=' NEUT1', VALE= (- 1.E-9, - 1.E-9, 1.E+9,1.E+9));
MA=DEFI_MATERIAU (ELAS_FO=_F (E=E_F, NU=NU_F,),);
CM=AFFE_MATERIAU (MAILLAGE=M,
AFFE=_F (TOUT= “YES”, MATER= MA),
AFFE_VARC=_F (NOM_VARC=' NEUT1', CHAMP_GD=CHYOUNG),
)