Code_Aster
®
Version
6.2
Titrate:
Pre and post-processor “composite thin hulls”
Date:
22/01/02
Author (S)
:
A. Mr. DONORE, Mr. BONNAMY
Key:
U2.02.03-B
Page
:
1/6
Instruction manual
U2.02 booklet: Elements of structure
HT-66/02/003/A
Organization (S):
EDF/AMA, AUSY France
Instruction manual
U2.02 booklet: Elements of structure
Document: U2.02.03
Note of use of Pre and Post-processor
“composite thin hulls”
Summary
The modeling of the thermomechanical behavior of a structure made up of a composite material
multi-layer breaks up into three stages:
·
determination of the mechanical magnitudes and thermal on the average surface of the hull,
i.e., the study of the relation stress-strains of the multi-layer composite from
characteristics of each layer and a simple space description of multi-layer, as described
in [R4.01.01].
This stage wants to be independent of the type of element used in the phase of calculation and constitutes it
preprocessor “composite thin hulls” of Aster,
·
calculation by finite elements, on the average surface of the hull,
·
the determination sleeps by layer, of the tensor of deformations, the tensor of stresses, and of
criterion of rupture says criterion of the maximum stress. This is carried out by the post-processor.
Code_Aster
®
Version
6.2
Titrate:
Pre and post-processor “composite thin hulls”
Date:
22/01/02
Author (S)
:
A. Mr. DONORE, Mr. BONNAMY
Key:
U2.02.03-B
Page
:
2/6
Instruction manual
U2.02 booklet: Elements of structure
HT-66/02/003/A
1 Preprocessor
The preprocessor must determine the coefficients of the matrix of rigidity, characterizing the relation
stress-strains, which in the case of brings back the hulls to a relation between the efforts
generalized (NR, M) and tensors of deformation (
E
) and of variation of curvature (
K
); It is added if
necessary to this relation generalized efforts of thermal origin
NR
HT
, M
HT
.
NR
M
= A B
B D
E
K
+
NR
HT
M
HT
This determination requires the following data:
·
characteristics of various constituent materials the multi-layer one (each layer can be
an isotropic material or an orthotropic material defined by a suitable number of constants
rubber bands).
Note:
Several layers can be of the same material.
·
direction of reference, definite on the average surface of the hull, and allowing to introduce
easily, orientation of the layers ones compared to the others; this direction of
reference is that defined by the key word
ORIENTATION
of
HULL
by the operator
AFFE_CARA_ELEM
(see [U4.24.01]).
·
of a space description of the multi-layer one which includes/understands, layer by layer, (while beginning by
the sub-base relative than the normal with the element), the data of material, of
the thickness and of the orientation of the axes of orthotropism of material compared to the axis of
reference.
Code_Aster
®
Version
6.2
Titrate:
Pre and post-processor “composite thin hulls”
Date:
22/01/02
Author (S)
:
A. Mr. DONORE, Mr. BONNAMY
Key:
U2.02.03-B
Page
:
3/6
Instruction manual
U2.02 booklet: Elements of structure
HT-66/02/003/A
1.1
Definition of a material
The definition of material is done using the operator
DEFI_MATERIAU
[U4.23.01].
to subdue
I
[to subdue] = DEFI_MATERIAU
(
| /ELAS:
(
For a material
E
:
yg
[R]
isotropic,
NAKED
: naked
[R]
RHO
:
rho
[R]
ALPHA:
dil [R]
)
/
ELAS_FO
:
(
E:
yg
[
function “TEMP”]
NAKED
: naked
[
function “TEMP”]
RHO
:
rho
[R]
ALPHA
: dil
[
function “TEMP”]
)
for a material
/
ELAS_ORTHO
:
(
orthotropic (L, T)
E_L:
ygl
[R]
axes of orthotropism,
E_T
: Ygt
[R]
NU_LT
: nult [R]
G_LT
:
glt
[R]
RHO:
rho [R]
according to L in traction
ALPHA_L: dil
[R]
according to L in compression
ALPHA_T: known as
[R]
according to T in traction
XT
: trl
[R]
stresses according to
T in compression
TESTSTEMXÇ
: neck
[R]
with in
shearing
YT
: trt
[R]
TESTSTEMYÇ
: cot
[R]
rupture
S_LT
:
cis
[R]
for a material
)
isotropic,
| /THER:
(
CP
:
CP
[R]
LAMBDA
:
[R]
)
/
THER_FO
:
(
for a material
CP:
CP
[
function “INST”]
orthotropic (L, T) axes
LAMBDA
:
[
function “INST”]
of orthotropism NR centers
)
normal on surface
/
THER_ORTHO
:
(
average.
CP:
CP
[
function “INST”]
LAMBDA_L:lal
[
function “INST”]
LAMBDA_T:lat
[
function “INST”]
LAMBDA_N:
[
function “INST”]
)
);
Note:
·
the application of a criterion of rupture, whatever it is, requires the knowledge of the stresses
with the rupture in traction, compression and shearing. They are characteristics of material
that one can introduce on the level of the operator
DEFI_MATERIAU
, by the key words
XT,
TESTSTEMXÇ
,
YT
,
TESTSTEMYÇ
and
S_LT
, and which is exploited by postprocessing.
·
it is possible to define a material of which elastic stresses
E_L,
E_T
,
NAKED
_
LT
and
G_LT
are identically null.
That is particularly useful in the case of a material “sandwich” of which the central layer
does not intervene by its rigidity but only by the spacing which it imposes on the layers located
on both sides.
Code_Aster
®
Version
6.2
Titrate:
Pre and post-processor “composite thin hulls”
Date:
22/01/02
Author (S)
:
A. Mr. DONORE, Mr. BONNAMY
Key:
U2.02.03-B
Page
:
4/6
Instruction manual
U2.02 booklet: Elements of structure
HT-66/02/003/A
1.2
Definition of a direction of reference
The direction of reference is defined by projection
X
1
of a vector
V
chosen by the user by
data of 2 angles, on the tangent level with the hull [R4.01.01]
Angle 1 = X, V
proj (X, Y)
Angle 2 = V
proj (X, Y)
, V with X, Y, Z identify total.
The data of these two angles, is done using the operator
AFFE_CARA_ELEM
[U4.24.01].
[will cara] = AFFE_CARA_ELEM
(
MODEL: MOD
[model]
HULL:
(
/
ALL:
“YES”
/
NET:
lma [l_maille]
/
GROUP_MA: lgma [l_gr_maille]
THICK:
thick
[R]
ANGL_REP:
angle1, angle2
[l_R]
COURB
: curvature
[R]
)
);
Note:
Currently, only one finite element of thin hull makes it possible to treat orthotropic materials:
the cylindrical element of hull (
MODELING
:
'COQU_CYL
'specified by
AFFE_MODELE
), for
which the radius of curvature 1/R is given by the key word
COURB
.
The orthotropic behavior for modelings
DKT
and
DST
is under development.
1.3
Definition of the space description of the multi-layer one
The definition of multi-layer is done using the operator
DEFI_COQU_MULT
:
multi-layer = DEFI_COQU_MULT
(
SLEEP
:
(
THICK: thick
thickness of layer I
MATER
:
[chechmate]
associated layer I
ORIENTATION
:
orien
orientation of the layer
compared to the reference axis
(angle in degrees)
IMPR:
/
0
/1
/2
)
);
The key word factor
SLEEP
appears time as many as there are layers in composite material.
The layers are given sub-base than the roadbase while referring than the normal
with the element.
Code_Aster
®
Version
6.2
Titrate:
Pre and post-processor “composite thin hulls”
Date:
22/01/02
Author (S)
:
A. Mr. DONORE, Mr. BONNAMY
Key:
U2.02.03-B
Page
:
5/6
Instruction manual
U2.02 booklet: Elements of structure
HT-66/02/003/A
2 Post-processor
The role of the post-processor, is to provide, layer by layer, the state of the strains, the stresses
and an evaluation of the criterion of rupture, known as of the maximum stress.
Its use is done using the operator
CALC_CHAM_ELEM
:
result = CALC_CHAM_ELEM
(
MODEL
:
Mo
[model]
CHAM_MATER
:
chmater [cham_mater]
CARA_ELEM
:
carac
[cara_elem]
NUME_COUCHE
:
[I]
NIVE_COUCHE
:
/
“SUP”
[K3]
/
“INF”
[K3]
/
“MOY”
[K3]
INST
:
/
tps
[R]
/
0.
{DEFECT]
/
OPTION
:
/
“SIEF_ELGA_DEPL”
[K16]
/
“SIGM_ELNO_DEPL”
/
“EFGE_ELNO_DEPL”
/
“DPGE_ELNO_DEPL”
/
“EPSI_ELNO_DEPL”
/
“CRIT_ELNO_RUPT”
DEPL
:
depl [cham_no_DEPL_R]
CHARGE
:
charge
[load]
CHAM_ELEM
:
carac
/
[cham_elem_SIEF_R]
[cham_elem_EPSI_R]
/
OPTION
:
/
“FLUX_ELGA_TEMP”
[K16]
/
“FLUX_ELNO_TEMP”
[K16]
TEMP
:
temp [cham_no_TEMP_R]
);
The result is according to the option chosen by the user, a tensor of deformations, a tensor of
stresses, a criterion of rupture…
In the case of a criterion of rupture the calculated sizes are:
CR
X
X
X
X
L
L
T
L
T
L
C
L
C
=
= -
<
if
if
0
0
:
:
breaking stress in traction along the axis L
(1ère direction of orthotropism),
breaking stress in compression along the axis
L
.
CR
Y
Y
Y
Y
TT
TT
T
L
T
TT
C
L
C
=
= -
<
if
if
0
0
:
:
breaking stress in traction along the axis T
(2nd direction of orthotropism),
breaking stress in compression along the axis
T
.
CR
S LT
S LT
LT
LT
=
_
_
:
breaking stress in shearing in the plan
L, T.
The breaking stresses are introduced using the operator
DEFI_MATERIAU
as indicated in
[§ 1.1].
The result is calculated, with the choice of the user, on the upper surface, lower or average (word
key
NIVE_COUCHE
), of a layer specified by the key word
NUME_COUCHE
.
Code_Aster
®
Version
6.2
Titrate:
Pre and post-processor “composite thin hulls”
Date:
22/01/02
Author (S)
:
A. Mr. DONORE, Mr. BONNAMY
Key:
U2.02.03-B
Page
:
6/6
Instruction manual
U2.02 booklet: Elements of structure
HT-66/02/003/A
Intentionally white left page.