Abstract
Repeated exposure to rapid temperature transients causes
gradual damage in material. This is
called thermal fatigue. Thermal fatigue is an important
degradation mechanism in nuclear power plant
components and can limit the plant lifetime where thermal
loads are present, e.g., due to turbulent mixing
or change in plant operating conditions. The effects of
the thermal load cycles include residual stresses,
hardening or softening of the material and, finally,
crack initiation and growth.
Traditionally, thermal fatigue crack growth rates are
estimated from the stress intensity factors
calculated from uncracked stress distributions and the
Paris' law. In the low-cycle regime, the use of
weight function based stress intensity factor solutions
derived under linear elastic assumptions is
questionable due to considerable plasticity. On the other
hand, numerical contour integral techniques are
ill-suited for thermal cyclic loading.
In this work, the use of the crack opening displacement
as the crack driving force parameter is
evaluated through simulations of a low-cycle thermal
fatigue experiments. The use of the crack tip
opening displacement avoids the traditional limitations
in the numerical evaluation of the J-integral. The
unique relationship between the crack opening
displacement and J-integral is derived and the crack
driving force is used in a crack growth assessment. The
results show that the crack driving force
calculated from the uncracked stress distributions
overestimates the crack driving force significantly (as
compared to values calculated from the crack opening
displacement). The crack growth rate calculated
with the Paris' law is in good agreement with the
experimental results, when the crack driving force is
computed from the crack opening displacement.
Original language | English |
---|---|
Title of host publication | SMiRT-24, Conference on Structural Mechanics in Reactor Technology |
Publisher | International Association for Structural Mechanics in Reactor Technology IASMiRT |
Number of pages | 10 |
Publication status | Published - 2017 |
MoE publication type | A4 Article in a conference publication |
Event | 22nd International Conference on Structural Mechanics in Reactor Technology 2013, SMiRT 22 - San Francisco, United States Duration: 18 Aug 2013 → 23 Aug 2013 Conference number: 23 |
Publication series
Series | Transactions of the International conference on structural mechanics in reactor technology |
---|---|
ISSN | 0167-563X |
Conference
Conference | 22nd International Conference on Structural Mechanics in Reactor Technology 2013, SMiRT 22 |
---|---|
Abbreviated title | SMiRT 22 |
Country/Territory | United States |
City | San Francisco |
Period | 18/08/13 → 23/08/13 |