Code_Aster ®
Version
7.4
Titrate:
Operator POST_K_BETA


Date:
08/02/05
Author (S):
A. DAHL, S. BUGAT, R. FERNANDES Key
:
U4.82.07-B Page
: 1/6

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

Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
Document: U4.82.07

Operator POST_K_BETA

1 Goal

Analyze harmfulness of defect by the method K-beta.

This method aims to evaluate the factors of margins with respect to the starting of the tear
coating (in first point of the defect) and with respect to the brittle fracture of the base metal or of
welded joint (in second point of the defect).

POST_K_BETA calculates the stress intensity factors to the two points of the defect, using
constraints with the nodes resulting from the mechanical resolution [R7.02.10].

This method calculates the stress intensity factors on models in which the fissure
is not represented. It uses the constraints with the nodes along a segment of support of the defect
postulated. The stress intensity factors obtained are those of a defect under coating of
elliptic profile, under the assumption of an elastic behavior of materials.
The “correction”, specific to the defects under coating stuck to the interface, makes it possible to hold account
plasticization with the two points of the fissure side coating (point A) and side base metal
(point B).

Product a concept of the type counts.
Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A

Code_Aster ®
Version
7.4
Titrate:
Operator POST_K_BETA


Date:
08/02/05
Author (S):
A. DAHL, S. BUGAT, R. FERNANDES Key
:
U4.82.07-B Page
: 2/6

2 Syntax
tk [table] = POST_K_BETA (



MAILLAGE

=
my,
[grid]



MATER_REV = chechmate, [material]




EPAIS_REV
=
epais_rev,



[R]



FISSURE =_F (

| DECALAGE =/- 2.10-4,
[DEFAUT]

/shift, [R]

| PROFONDEUR =
depth, [R]

| LONGUEUR =
length, [R]

| ORIENTATION =/“CIRC”,
/“LONGI”,








),



K1D = (_F (

| TABL_MECA_REV =
table_rev, [table]

| TABL_MECA_MDB =
table_mdb, [table]

| TABL_THER =
table_ther, [table]

| INTITULE =
heading, [K]









),),



TITER
=
titrate
,
[l_K]


)

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

Code_Aster ®
Version
7.4
Titrate:
Operator POST_K_BETA


Date:
08/02/05
Author (S):
A. DAHL, S. BUGAT, R. FERNANDES Key
:
U4.82.07-B Page
: 3/6

3 Operands

Axisymmetric schematization of a section of tank with presence of a defect under-coating.

Center of basic Métal
the tank
Depth
defect
Coating
Shift
defect
With
B
laughed
erev
emdb


3.1 Operand
MAILLAGE

Concept of the grid type.

3.2 Operand
MATER_REV

Name of the concept of the material type defining material constituting the coating. Necessary for
to recover the yield stresses, for the plastic correction of the stress intensity factors.

3.3 Operand
EPAIS_REV

Thickness of the coating. Necessary for the correction of the stress intensity factors by
factors of edges and for the plastic correction.

3.4 Word
key
FISSURE

Key word factor for the geometrical characterization of the defect. It can be used only only once.

3.4.1 Operand
DECALAGE

Shift of the fissure in the coating starting from the interface coating/base metal. To note
that the shift is necessarily negative. By defect, shift = ­ 2.10­4.

3.4.2 Operand
PROFONDEUR

Radial dimension of the defect.

3.4.3 Operand
LONGUEUR

The second dimension of the defect (axial or orthoradiale according to the orientation of the defect).

3.4.4 Operand
ORIENTATION

Characterization of the orientation of the defect: “CIRC” for a circumferential defect,

“LONGI” for a longitudinal defect.
Handbook of Utilization
U4.8- booklet: Postprocessing and dedicated analyzes
HT-66/05/004/A

Code_Aster ®
Version
7.4
Titrate:
Operator POST_K_BETA


Date:
08/02/05
Author (S):
A. DAHL, S. BUGAT, R. FERNANDES Key
:
U4.82.07-B Page
: 4/6

3.5 Word
key
K1D

Key word factor for the characterization of the thermomechanical transient. The repetition of this key word is
possible.

3.5.1 Operands
TABL_MECA_REV and TABL_MECA_MDB

Tables providing the transient of the constraints undergone by the tank during the history of
loading, respectively side coating (of point A of the defect to the interface) and side metal of
base (interface with the point B of the defect).

3.5.2 Operand
TABL_THER

Count providing the thermal transient in the tank during the history of the loading of
point A with the point B.

3.5.3 Operand
INTITULE

Heading to specify the group of nodes considered.

3.6 Operand
TITER

Titrate attached to the concept produced by this operand [U4.03.01].

4 Example

Examples of use of command POST_K_BETA are provided in the case test EPICU01.
Before the use of command POST_K_BETA, it is necessary to record the constraints and them
temperatures along the defect.
In the example below, the paths chem1, chem2 and chem3 on which statements of
constraint and of temperature will be carried out are first of all defined.

Definition of chem1 which goes from the point of the defect side coating until the interface.

CHEM1=INTE_MAIL_2D (GRID = MALL,
GROUP_MA
=
“R”,
INFO
=
2,
PRECISION
=
1.0E-6,
DEFI_SEGMENT
=
_F (
ORIGINE
=
(DEBFIS,
0.0),
GROUP_NO_EXTR
=
“Pi”,













)






)

Definition of chem2 which goes from the interface to the point of the defect side base metal.

CHEM2=INTE_MAIL_2D (GRID = MALL,
GROUP_MA
=
“Me,
PRECISION
=
1.0E-6,
INFO
=
2,
DEFI_SEGMENT
=
_F (
GROUP_NO_ORIG
=
“Pi”,
EXTREMITE
=
(EXTRABS,
0.0),













)






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

Code_Aster ®
Version
7.4
Titrate:
Operator POST_K_BETA


Date:
08/02/05
Author (S):
A. DAHL, S. BUGAT, R. FERNANDES Key
:
U4.82.07-B Page
: 5/6

Definition of chem3 which goes from the point of the defect side coating to that side base metal.

CHEM3=INTE_MAIL_2D (GRID = MALL,
PRECISION
=
1.0E-6,
INFO
=
2,
DEFI_SEGMENT
=
_F (
ORIGINE
=
(DEBFIS,
0.0),
EXTREMITE
=
(EXTRABS,
0.0),













)






)

Statement of the constraints on chem1: the constraints are recorded on the part of the defect located in
coating.

S1_G=POST_RELEVE_T (ACTION=_F
(CHEMIN
=
CHEM1,
INTITULE
=
“GLOBAL1”,
RESULTAT
=
SIG,
TOUT_CMP
=
“OUI”,
NOM_CHAM
=
“SIGM_ELNO_DEPL”,
LIST_INST
=
LINST_ME,
OPERATION
=
“EXTRACTION”,










)






)

Statement of the constraints on chem2: the constraints are recorded on the part of the defect located in
base metal.

S2_G=POST_RELEVE_T (ACTION=_F
(CHEMIN
=
CHEM2,
INTITULE
=
“GLOBAL2”,
RESULTAT
=
SIG,
TOUT_CMP
=
“OUI”,
NOM_CHAM
=
“SIGM_ELNO_DEPL”,
LIST_INST
=
LINST_ME,
OPERATION
=
“EXTRACTION”,










)






)

Statement of the temperatures on chem3: the temperature is recorded along the defect.

TEMP_G=POST_RELEVE_T (ACTION=_F
(CHEMIN
=
CHEM3,
INTITULE
=
“GLOBAL3”,
RESULTAT
=
TEMP,
TOUT_CMP
=
“OUI”,
NOM_CHAM
=
“TEMP”,
LIST_INST
=
LINST_TH,
OPERATION
=
“EXTRACTION”,










)






)

After having taken these various readings, the calculation of the stress intensity factor can be done
indeed using command POST_K_BETA.

TB_KBETA = POST_K_BETA (GRID = MALL,
MATER_REV
=
MAME_RE2,
EPAIS_REV
=
EPREV,
FISSURE =
_F
(
PROFONDEUR
=
6.,
LONGUEUR


=
60.,
DECALAGE


=
- 1.E-05,
ORIENTATION=
“CIRC”
),
K1D


= (_F (TABL_MECA_REV = S1_G,
TABL_MECA_MDB
=
S2-G,
TABL_THER




=
TEMP_G,
INTITULE





=
“NOEINF”,),),
TITER
=

'FIC
PAR
METHODE
K-BETA'







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

Code_Aster ®
Version
7.4
Titrate:
Operator POST_K_BETA


Date:
08/02/05
Author (S):
A. DAHL, S. BUGAT, R. FERNANDES Key
:
U4.82.07-B Page
: 6/6

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

Outline document