Nordisk kernesikkerhedsforskning
Norrænar kjarnöryggisrannsóknir
Pohjoismainen ydinturvallisuustutkimus
Nordisk kjernesikkerhetsforskning
Nordisk kärnsäkerhetsforskning
Nordic nuclear safety research
NKS-126
ISBN 87-7893-188-6
Simulation and Analysis of Data for Enhancing
Low Cycle Fatigue Test Procedures
Urpo Sarajärvi and Otso Cronvall
VTT Technical Research Centre of Finland
April 2006
,Abstract
The simulation and analysis of data for enhancing low cycle fatigue test proce-
dures is discussed in this report. The analysed materials are an austenitic
stainless piping steel and an austenitic weld material. This project continues the
work performed in 2003 and 2004. The fatigue test data treatment application
developed within the project in 2004 for the preparation of the fatigue data has
been developed further. Also, more fatigue test data has been analysed with the
application than in 2004. In addition to this numerical fatigue simulations were
performed with FEM code ABAQUS. With the fatigue test data treatment applica-
tion one can e.g. both calculate cyclically certain relevant characteristic values,
e.g. elastic range, and form a set of certain cyclical parameter values needed as
a part of ABAQUS analysis input files. The hardening properties of metals were
modelled with both isotropic and kinematic hardening models.
The further development of the application included trimming of the analysed
data, and consequently trimming of resulting hardening parameters. The need for
the trimming arose from the fact that the analysed fatigue test data presents
some scatter caused by the limited accuracy of the test equipment and the sam-
pling rate. The hardening parameters obtained from the application analysis re-
sults were used in the subsequent ABAQUS analyses, and then the fatigue test
data were compared with the ABAQUS simulation results. After finding a proce-
dure to trim result data to get smooth curves for cyclic hardening, hardening and
softening could be reproduced in ABAQUS analysis with a reasonable accuracy.
The modelling of the fatigue induced initiation and growth of cracks was not
considered in this study. On the other hand, a considerable part of the fatigue life
of nuclear power plant (NPP) piping components is spent in the phase preceding
the initiation and growth of cracks.
Key words
low cycle fatigue, steel, stainless, austenitic, material model, finite element model
NKS-126
ISBN 87-7893-188-6
Electronic report, April 2006
The report can be obtained from
NKS Secretariat
NKS-775
P.O. Box 49
DK - 4000 Roskilde, Denmark
Phone +45 4677 4045
Fax +45 4677 4046
www.nks.org
e-mail
,RESEARCH REPORT TUO72-056604 4.4.2006
Simulation and Analysis of Data for Enhancing
Low Cycle Fatigue Test Procedures
Authors Sarajärvi, Urpo, Cronvall, Otso
Confidentiality: Public
, RESEARCH REPORT TUO72-056604
1 (32)
Report’s title
Simulation and Analysis of Data for Enhancing Low Cycle Fatigue Test Procedures
Customer Order reference
VYR
Project name Project number /Short name
INPUT VÄSYMA G5SU01043
Author(s) Pages
Sarajärvi, Urpo, Cronvall, Otso 32 /
Key words Report identification code
TUO72-056604
Summary
The simulation and analysis of data for enhancing low cycle fatigue test procedures is discussed in this report.
The analysed materials are an austenitic stainless piping steel and an austenitic weld material. This project
continues the work performed in 2003 and 2004. The fatigue test data treatment application developed within the
project in 2004 for the preparation of the fatigue data has been developed further. Also, more fatigue test data has
been analysed with the application than in 2004. In addition to this numerical fatigue simulations were performed
with FEM code ABAQUS. With the fatigue test data treatment application one can e.g. both calculate cyclically
certain relevant characteristic values, e.g. elastic range, and form a set of certain cyclical parameter values needed
as a part of ABAQUS analysis input files. The hardening properties of metals were modelled with both isotropic
and kinematic hardening models.
The further development of the application included trimming of the analysed data, and consequently trimming
of resulting hardening parameters. The need for the trimming arose from the fact that the analysed fatigue test
data presents some scatter caused by the limited accuracy of the test equipment and the sampling rate. The
hardening parameters obtained from the application analysis results were used in the subsequent ABAQUS
analyses, and then the fatigue test data were compared with the ABAQUS simulation results. After finding a
procedure to trim result data to get smooth curves for cyclic hardening, hardening and softening could be
reproduced in ABAQUS analysis with a reasonable accuracy.
The modelling of the fatigue induced initiation and growth of cracks was not considered in this study. On the
other hand, a considerable part of the fatigue life of nuclear power plant (NPP) piping components is spent in the
phase preceding the initiation and growth of cracks.
Confidentiality: Public
Espoo 04.04.2006
Signatures
Pentti Kauppinen Urpo Sarajärvi Arja Saarenheimo
Deputy Technology Manager Research Scientist Checked
VTT’s contact address
P.O. Box 1000, FI-02044 VTT
Distribution (customer and VTT):
STUK: Registry (4), Keskinen R. (1), Hytönen Y. (1); FNS: Neuvonen A. (1);
TVO: Pulkkinen E. (1 kpl); NKS: Kierkegaard J. (1); VTT: Archive (1)
The use of the name of the Technical Research Centre of Finland (VTT) in advertising or publication in part of
this report is only permissible by written authorisation from the Technical Research Centre of Finland.
Norrænar kjarnöryggisrannsóknir
Pohjoismainen ydinturvallisuustutkimus
Nordisk kjernesikkerhetsforskning
Nordisk kärnsäkerhetsforskning
Nordic nuclear safety research
NKS-126
ISBN 87-7893-188-6
Simulation and Analysis of Data for Enhancing
Low Cycle Fatigue Test Procedures
Urpo Sarajärvi and Otso Cronvall
VTT Technical Research Centre of Finland
April 2006
,Abstract
The simulation and analysis of data for enhancing low cycle fatigue test proce-
dures is discussed in this report. The analysed materials are an austenitic
stainless piping steel and an austenitic weld material. This project continues the
work performed in 2003 and 2004. The fatigue test data treatment application
developed within the project in 2004 for the preparation of the fatigue data has
been developed further. Also, more fatigue test data has been analysed with the
application than in 2004. In addition to this numerical fatigue simulations were
performed with FEM code ABAQUS. With the fatigue test data treatment applica-
tion one can e.g. both calculate cyclically certain relevant characteristic values,
e.g. elastic range, and form a set of certain cyclical parameter values needed as
a part of ABAQUS analysis input files. The hardening properties of metals were
modelled with both isotropic and kinematic hardening models.
The further development of the application included trimming of the analysed
data, and consequently trimming of resulting hardening parameters. The need for
the trimming arose from the fact that the analysed fatigue test data presents
some scatter caused by the limited accuracy of the test equipment and the sam-
pling rate. The hardening parameters obtained from the application analysis re-
sults were used in the subsequent ABAQUS analyses, and then the fatigue test
data were compared with the ABAQUS simulation results. After finding a proce-
dure to trim result data to get smooth curves for cyclic hardening, hardening and
softening could be reproduced in ABAQUS analysis with a reasonable accuracy.
The modelling of the fatigue induced initiation and growth of cracks was not
considered in this study. On the other hand, a considerable part of the fatigue life
of nuclear power plant (NPP) piping components is spent in the phase preceding
the initiation and growth of cracks.
Key words
low cycle fatigue, steel, stainless, austenitic, material model, finite element model
NKS-126
ISBN 87-7893-188-6
Electronic report, April 2006
The report can be obtained from
NKS Secretariat
NKS-775
P.O. Box 49
DK - 4000 Roskilde, Denmark
Phone +45 4677 4045
Fax +45 4677 4046
www.nks.org
,RESEARCH REPORT TUO72-056604 4.4.2006
Simulation and Analysis of Data for Enhancing
Low Cycle Fatigue Test Procedures
Authors Sarajärvi, Urpo, Cronvall, Otso
Confidentiality: Public
, RESEARCH REPORT TUO72-056604
1 (32)
Report’s title
Simulation and Analysis of Data for Enhancing Low Cycle Fatigue Test Procedures
Customer Order reference
VYR
Project name Project number /Short name
INPUT VÄSYMA G5SU01043
Author(s) Pages
Sarajärvi, Urpo, Cronvall, Otso 32 /
Key words Report identification code
TUO72-056604
Summary
The simulation and analysis of data for enhancing low cycle fatigue test procedures is discussed in this report.
The analysed materials are an austenitic stainless piping steel and an austenitic weld material. This project
continues the work performed in 2003 and 2004. The fatigue test data treatment application developed within the
project in 2004 for the preparation of the fatigue data has been developed further. Also, more fatigue test data has
been analysed with the application than in 2004. In addition to this numerical fatigue simulations were performed
with FEM code ABAQUS. With the fatigue test data treatment application one can e.g. both calculate cyclically
certain relevant characteristic values, e.g. elastic range, and form a set of certain cyclical parameter values needed
as a part of ABAQUS analysis input files. The hardening properties of metals were modelled with both isotropic
and kinematic hardening models.
The further development of the application included trimming of the analysed data, and consequently trimming
of resulting hardening parameters. The need for the trimming arose from the fact that the analysed fatigue test
data presents some scatter caused by the limited accuracy of the test equipment and the sampling rate. The
hardening parameters obtained from the application analysis results were used in the subsequent ABAQUS
analyses, and then the fatigue test data were compared with the ABAQUS simulation results. After finding a
procedure to trim result data to get smooth curves for cyclic hardening, hardening and softening could be
reproduced in ABAQUS analysis with a reasonable accuracy.
The modelling of the fatigue induced initiation and growth of cracks was not considered in this study. On the
other hand, a considerable part of the fatigue life of nuclear power plant (NPP) piping components is spent in the
phase preceding the initiation and growth of cracks.
Confidentiality: Public
Espoo 04.04.2006
Signatures
Pentti Kauppinen Urpo Sarajärvi Arja Saarenheimo
Deputy Technology Manager Research Scientist Checked
VTT’s contact address
P.O. Box 1000, FI-02044 VTT
Distribution (customer and VTT):
STUK: Registry (4), Keskinen R. (1), Hytönen Y. (1); FNS: Neuvonen A. (1);
TVO: Pulkkinen E. (1 kpl); NKS: Kierkegaard J. (1); VTT: Archive (1)
The use of the name of the Technical Research Centre of Finland (VTT) in advertising or publication in part of
this report is only permissible by written authorisation from the Technical Research Centre of Finland.
