Multi‐scale fatigue crack propagation in 304 stainless steel: experiments and modelling

Mat Design & Process Comms

2019

The behaviors of short fatigue crack remain to be one of the most challenging topics in fracture mechanics. It is widely accepted that the process of short fatigue crack can be divided as microstructure‐sensitive stage and microstructure‐independent stage. The inherent multiscaling characteristics necessitates the formulation of multiscale short fatigue crack growth model. One crucial way to address the concern is to explore physically reasonable expression of crack‐tip driving force. This paper briefly reviews the short fatigue crack growth models through two approaches. One way is the further modification of conventional stress intensity factor (SIF) range. The other way is to seek the replacement of SIF range, by employing J‐integral and strain energy density factor. Reflections on the present multiscale models are summarized in the concluding remarks.

“…The fixed material constant makes the model limited to certain materials. This barrier is partially overcome by replacing power exponent with m in the following studies

\frac{da}{dN} = C {(Δ K - Δ K_{th})}^{m} .

…”

Section: Modification Of δKmentioning

confidence: 99%

“…A further improvement on Chan‐Lankford model is put on the local yielding stress

σ_{y}^{m}

. Ye et al introduce the fine grain strengthen theory into the definition of

σ_{y}^{m}

. The framework of Ye model is based on Zheng model, where the threshold Δ K th is determined by EI Haddad model .…”

Section: Modification Of δKmentioning

confidence: 99%

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Short review on multiscale short fatigue crack growth model

Hou

Mat Design & Process Comms

2019

“…The UniGrow model is further modified by considering SC and LC growth behaviors in a unified manner 16 . A series of researches are initiated to investigate the fatigue crack growth behaviors in metal alloys 17–20 . It is noted that the crack propagation at the MSC, PSC, and LC stages is incorporated in one single model 19,20 .…”

Section: Introductionmentioning

confidence: 99%

Crack initiation and propagation from geometric microdefects: Experiment and transition fatigue behavior

Fatigue Fract Eng Mat Struct

Ferro

et al. 2021

The present work aims to study short fatigue crack initiation and propagation induced by geometric microdefects. An empirical approach is used to evaluate the microstructural influences on crack growth behavior. Small fatigue crack test on titanium alloy Ti‐6Al‐4V is performed to investigate the crack induced from a geometric microdefect. Analyses on crack initiation and fracture are respectively performed to study the microstructural influences on the stages of initiation and fracture. Subsequently, an empirical multiscale model is employed to predict the short fatigue crack propagation of alloys underlining the transition features. Grain size variation is adopted to reflect the main microstructural contribution to the short crack propagation. An alpha factor is defined to demonstrate the transition interim from microstructurally short crack to physically short crack stages. Furthermore, a relationship between transition factor and grain size is correlated. The results indicate that the value of transition factor tends to decrease with the augment of average grain size. The empirical approach is validated through a variety of fatigue experimental data of alloys including Ti‐6Al‐4V, 2024‐T3, and GH4169.

“…Not surprisingly, the concept of microstructure dissimilitude is introduced by Chan and Lankford . More efforts have been initiated to better illustrate the effects of microstructure dissimilitude …”

Section: Introductionmentioning

confidence: 99%

Microstructure dissimilitude factor for multiscale short fatigue crack growth model

Mat Design & Process Comms

Wang

et al. 2019

Fatigue crack growth behaviors of metal alloys are inherently multiscaling.The dual stage advancement in ductile polycrystals can be divided as microstructure-sensitive stage I and microstructure-independent stage II.Emphasis is placed on stage I of multiscale short fatigue crack growth behaviors in this paper. A microstructure dissimilitude factor p is defined to highlight the effects of microstructural dissimilitude at the stage of the microstructurally small crack (MSC). Fatigue tests of Ti-6Al-4V alloy are performed for reference. By incorporating the factor p, the proposed short fatigue crack growth model offers relatively better predictive curves at MSC stage.