Low-cycle fatigue crack initiation and propagation from controlled surface imperfections in nuclear steels

Influence of mean stress and pressurized water reactor environment on the fatigue behavior of a 304L austenitic stainless steel

“…The values of C , m , N t , and a t for each investigated condition are assembled in Table 3. This transition in crack growth rate was previously observed in 304 stainless steel on striation spacing as on crack growth rates derived from direct current potential drop (DCPD) monitoring method, at diverse strain amplitudes and strain rates and in different media 6,34–36 . This can be attributed to a lower sensitivity to Δ K ε (or crack depth) during the propagation of short cracks than the macro‐crack propagation, firstly reported as a “short‐crack” effect 37 .…”

“…This transition in crack growth rate was previously observed in 304 stainless steel on striation spacing as on crack growth rates derived from direct current potential drop (DCPD) monitoring method, at diverse strain amplitudes and strain rates and in different media. 6,[34][35][36] This can be attributed to a lower sensitivity to ΔK ε (or crack depth) during the propagation of short cracks than the macro-crack propagation, firstly reported as a "short-crack" effect. 37 Except for the case with mean stress application in air, a t is comprised from 200 to 900 μm, which is consistent with the threshold crack depth for the transition from a "Physically short crack" to a "Long crack" regime as suggested by Ould-Amer 38 in 304 stainless steel.…”

Full-field analysis of damage under complex thermomechanical loading

“…To represent strain controlled fatigue crack growth rate, the K ε concept is straightforward in many cases, e.g. see [50,51], thus the Figure 10(b) shows the micro-crack growth rate function of ∆K ε ≃ ∆ε √ πa. Of course this constitutes a coarse assumption, by ignoring any correction in shape factor associated to each specimen geometry, but should be seen as an attempt to gain knowledge in FCGR sensitivity to TMF loadings.…”

Fatigue crack growth under large scale yielding condition: a tool based on explicit crack growth

“…First, FCGR models are either local or non-local, however this point is a requirement to limit the mesh dependency of FCGR assessment. Exception made of 𝐽 and CTOD based models, most models consider a stress or a strain amplitude, associated to non-linear elasticity to mimic viscoplastic behavior (Haigh and Skelton 1978;Kamaya 2015;Cussac 2020;Cussac et al 2020;Ravi Chandran 2018). This constitutes a second drastic limitation, considering FEA for structure applications.…”