Code_Aster ®
Version
4.0
Titrate:
SZLZ101 Calcul of the damage/Méthode RAINFLOW
Date:
19/01/98
Author (S):
A. Mr. DONORE
Key:
V9.01.101-A Page:
1/6
Organization (S): EDF/IMA/MN
Handbook of Validation
V9.01 booklet: Tire
Document: V9.01.101
SZLZ101 - Calcul of the damage/Méthode RAINFLOW
Summary:
The purpose of this test is calculation of the damage starting from a history of loading in constraints.
Starting from a simple history of loading defined by DEFI_FONCTION [U4.21.02], one extracts the cycles
elementary by the method of counting of cycles of the RAINFLOW [R7.04.01], then one calculates the damage
elementary associated each cycle, by interpolation on the curve of Wöhler of material.
One tests various possibilities of introducing the curve of Wöhler, as well as the taking into account of the coefficient of
elastoplastic concentration.
To finish, one determines the total damage undergone by the part by cumulating all the elementary damage by
linear rule of Miner.
This example is a test of validation of software POSTDAM developed by Département REME, provided in
the handbook of validation of version 1.0 of this software.
The results provided by operator POST_FATIGUE [U4.67.01] are completely identical to those provided by
software POSTDAM.
Handbook of Validation
V9.01 booklet: Tire
HI-75/96/038 - Ind A

Code_Aster ®
Version
4.0
Titrate:
SZLZ101 Calcul of the damage/Méthode RAINFLOW
Date:
19/01/98
Author (S):
A. Mr. DONORE
Key:
V9.01.101-A Page:
2/6
1
Problem of reference
1.1 Geometry
The analysis consists in determining the damage undergone by a part in a point to which one provides the history
of loading in constraints.
Starting from a simple history of loading defined by DEFI_FONCTION [U4.21.02], one extracts them
elementary cycles by the method of counting of cycles of RAINFLOW [R7.04.01], then one calculates
elementary damage associated each cycle, by interpolation on the curve of Wöhler of
material.
One tests various possibilities of introducing the curve of Wöhler and the taking into account or not of one
elastoplastic coefficient of concentration:
· The curve of Wöhler is defined in the form:
S
= alternate constraint = 1/2

=
alt
(E E
C
)
X
LOG10 (Salt)
2
3
1/NR if S > = S
0 + 1
+ 2
+
NR
has
has
X
has
X
a3 X
alt
I
= 10
D = 0.
if not
with:
EC. = Module of Young associated with the curve with fatigue with material,
E = Module of Young used to determine the constraints,
constants of the material a0, a1, a2 and a3,
and IF limit of endurance of material.
· The curve of Wöhler is defined in the same form and moreover one takes account of a coefficient of
elastoplastic concentration defined by:
K = 1.
if
< 3S
E
m

K = 1+ (1 - N)/3
- 1/
- 1
if
3
< <
E
(
Sm
) ((Nm))
S
3 m S
m
m
K = 1/N
if
3 m S
<


E
m
where
Sm is the acceptable maximum constraint,
and N and m two constants depending on material.
· The curve of Wöhler is defined in the analytical form of Basquin: D =

In Salt
To finish, one determines the total damage undergone by the part by cumulating all the damage
elementary by the linear rule of Miner.
1.2
Material properties
Parameters of definition of the curve of Wöhler:
a0
a1
a2
a3
EC.
E
SSL
55.81
­ 43.06
11.91
­ 1.16
200000.
200000.
180.
Parameters of definition of the elastoplastic coefficient of concentration Ke:
Sm
N
m
126.
0.3
1.7
Parameters of definition of the curve of Wöhler in the form analytical of Basquin:
With

1.001730939 E-14
4.065
History of the loading
T
0.
1.
2.
(T)
0.
1000.
0.
Handbook of Validation
V9.01 booklet: Tire
HI-75/96/038 - Ind A

Code_Aster ®
Version
4.0
Titrate:
SZLZ101 Calcul of the damage/Méthode RAINFLOW
Date:
19/01/98
Author (S):
A. Mr. DONORE
Key:
V9.01.101-A Page:
3/6
2
Reference solution
2.1
Method of calculation used for the reference solution
This test results from the handbook of validation of software POSTDAM version 1.0. Reference solutions
are given in this document.
2.2
Results of reference
The counting of the elementary cycles by method RAINFLOW leads to:
Nb_Cycl = 1
Cycle 1
Vale_Min:
0.
Vale_Max:
1000.
· First call to POST_FATIGUE:
Cycle 1
Too bad:
2.858503E4
The calculation of the total damage by linear office plurality of Miner:
Too bad: 2.858503E4
· Second call to POST_FATIGUE:
Cycle 1
Too bad:
1.224941E2
The calculation of the total damage by linear office plurality of Miner:
Too bad: 1.224941E2
· Third call to POST_FATIGUE:
Cycle 1
Too bad:
9.377005E4
The calculation of the total damage by linear office plurality of Miner:
Too bad: 9.377005E4
2.3
Uncertainty on the solution
Analytical solution.
2.4 References
bibliographical
[1]
Handbook of validation POSTDAM 1.0. Baker I., Vatin E. HP-14/93/016/B.
Handbook of Validation
V9.01 booklet: Tire
HI-75/96/038 - Ind A

Code_Aster ®
Version
4.0
Titrate:
SZLZ101 Calcul of the damage/Méthode RAINFLOW
Date:
19/01/98
Author (S):
A. Mr. DONORE
Key:
V9.01.101-A Page:
4/6
3 Modeling
With
3.1 Functionalities
tested
Order
POST_FATIGUE_T [U4.67.01].
Key word
Operands
HISTOIRE
SIGM:
COMPTAGE:
“RAINFLOW”
DOMMAGE:
“WOHLER”
MATER:`
CORR_KE:
“RCCM”
CUMUL:
“LINEAIRE”
INFO:
2
Key word
Operands
Keys
DEFI_MATERIAU
FATIGUE
A0:
[U4.23.01]
A1:
A2:
A3:
E_REFE:
SSL:
N_KE_RCCM:
M_KE_RCCM:
SM_KE_RCCM:
ELAS
E:
NAKED:
FATIGUE
A_BASQUIN:
BETA_BASQUIN:
Handbook of Validation
V9.01 booklet: Tire
HI-75/96/038 - Ind A

Code_Aster ®
Version
4.0
Titrate:
SZLZ101 Calcul of the damage/Méthode RAINFLOW
Date:
19/01/98
Author (S):
A. Mr. DONORE
Key:
V9.01.101-A Page:
5/6
4
Results of modeling A
4.1 Values
tested
Identification
Reference
Aster
% difference
NB_CYCL
1.
1.
0.
Cycle 1 VALE_MIN
0.
0.
0.
VALE_MAX
1000.
1000.
0.
First call to POST_FATIGUE:
Cycle 1 DAMAGE
2.858503E4
2.858503E4
0.
DOMM_CUMU
2.858503E4
2.858503E4
0.
Second call to POST_FATIGUE:
Cycle 1 DAMAGE
1.22494E2
1.22494E2
0.
DOMM_CUMU
1.22494E2
1.22494E2
0.
Third call to POST_FATIGUE:
Cycle 1 DAMAGE
9.377005E4
9.377005E4
0.
DOMM_CUMU
9.377005E4
9.377005E4
0.
4.2 Parameters
of execution
Version: 3.06.18
Machine: CRAY C90
Obstruction memory:
8 MW
Time CPU To use:
2.9181 seconds
Handbook of Validation
V9.01 booklet: Tire
HI-75/96/038 - Ind A

Code_Aster ®
Version
4.0
Titrate:
SZLZ101 Calcul of the damage/Méthode RAINFLOW
Date:
19/01/98
Author (S):
A. Mr. DONORE
Key:
V9.01.101-A Page:
6/6
5
Summary of the results
The results provided by Code_Aster are perfectly identical to the values of reference.
Handbook of Validation
V9.01 booklet: Tire
HI-75/96/038 - Ind A