Bayesian nonparametric analysis of crack growth rates in irradiated austenitic stainless steels in simulated BWR environments

2016 ◽  
Vol 307 ◽  
pp. 411-417
Author(s):  
Yasuhiro Chimi ◽  
Hisashi Takamizawa ◽  
Shigeki Kasahara ◽  
Keiko Iwata ◽  
Yutaka Nishiyama
Keyword(s):  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Austenitic Stainless Steels ◽  
Nonparametric Analysis ◽  
Bayesian Nonparametric ◽  
Crack Growth Rates

Crack Growth Rates of Irradiated Austenitic Stainless Steels in BWR Environments at 289°C

2007 ◽  
Author(s):  
O. K. Chopra ◽  
E. E. Gruber ◽  
B. Alexandreanu ◽  
Y. Chen ◽  
W. J. Shack
Keyword(s):  
Growth Rate ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Austenitic Stainless Steels ◽  
Compact Tension ◽  
Constant Load ◽  
Specimen Size ◽  
Crack Growth Rates ◽  
Sawtooth Waveform

Crack growth rate (CGR) data have been obtained in boiling water reactor environments on several grades of austenitic stainless steels, including weld heat-affected-zone and cast materials, that were irradiated up to 2.0 × 1021 n/cm2 (E > 1 MeV) (≈3 dpa). Crack growth tests were conducted on 1/4-T compact tension specimens subjected to either a sawtooth waveform with load ratios up to 0.7 and rise times up to 1000 s, or a constant load with or without periodic partial unloading. The results indicate significant enhancement of crack growth rates in the irradiated steels. The results are compared with data obtained from other studies. The existing CGR data are also reviewed to evaluate the effects of material composition, irradiation, and water chemistry on the CGRs in austenitic SSs. The significance of specimen size criteria is discussed.

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

Effect of Hold Periods on the Corrosion Fatigue Crack Growth Rates of Austenitic Stainless Steels in LWR Coolant Environments

2017 ◽  
Author(s):  
Norman Platts ◽  
David R. Tice ◽  
Alexandra Panteli ◽  
Sam Cruchley
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Corrosion Fatigue ◽  
Growth Rates ◽  
Austenitic Stainless Steels ◽  
Corrosion Fatigue Crack ◽  
Assessment Procedures ◽  
The Impact ◽  
Crack Growth Rates

Laboratory tests on austenitic stainless steel in simulated light water reactor (LWR) coolant environments have been shown to give rise to significant environmental enhancements of fatigue crack growth, especially at low cycling frequencies. The impact of LWR environments on fatigue crack growth has recently been codified in ASME code Case N-809 in terms of parameters such as rise time, stress intensity factor and load ratio. However, plant performance suggests that the application of these predicted environmental effects using current assessment procedures may be unduly pessimistic. This has led to significant number of studies of waveform shape (specifically hold periods) on the corrosion fatigue crack propagation in austenitic stainless steels in LWR environments. The main emphasis of this work addresses the ability of hold periods to cause retardation of environmental crack growth rates. There has been substantial variability in results of these studies with some authors reporting significant retardation whilst others have failed to observe retardation, or even reported additional environmental enhancement of crack growth rates for nominally similar loading waveforms. Although some of the variability may be accounted for in terms of material composition, there remains a considerable uncertainty both on the impact of holds, especially at different positions in the waveform, and the manner in which hold periods should be taken into account in plant assessments (e.g. in assessment procedures such as N-809). The current paper provides a critical review of published data on the effect of hold periods on corrosion fatigue in LWR environments as well as presenting new targeted data generation and analysis in order to rationalise the reported observations.

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