Analyses of KOP relationship to threshold Kmax,th

Kujawski, Daniel

doi:10.1016/j.engfracmech.2021.107561

Cited by 5 publications

(2 citation statements)

References 28 publications

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“…Noroozi et al 15,16 wrote a software called UNIGROW in terms of a two‐parameter driving force, without correcting for crack closure but accounting for residual stresses generated in front of the fatigue crack. In addition, other alternative approaches to crack closure have been proposed 17–20 …”

Section: Introductionmentioning

confidence: 99%

“…In addition, other alternative approaches to crack closure have been proposed. [17][18][19][20] It can be noted that 40 years after Elber published his papers 1,2 on crack closure, Wei in 2010 wrote a book on "Fracture Mechanics" 21 with no reference to crack closure and the analyses rested entirely on the role of environment in fatigue damage. But, Hertzberg et al in their book on "Deformation and Fracture Mechanics of Engineering Materials" in the latest 6th edition 22 published in 2022 has reference to crack closure.…”

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confidence: 99%

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On 50 years of fatigue crack closure dispute

Kujawski

Ricker

Sadananda

2023

Fatigue Fract Eng Mat Struct

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In this article, we examine the 50 years of observations and interpretations into the subject of fatigue crack closure in lab air and aqueous solutions: disputes and implications. Over this period, several closure concepts have been invoked to explain why the crack propagation threshold ΔKth should reduce with load ratio R. Among these, three types are the most popular and these are closure induced by crack (i) plasticity (PICC), (ii) oxides (OICC), and (iii) roughness (RICC). Therefore, these three and their role in shielding the fatigue crack tip are critically examined. This analysis finds that the reduction in ΔKth with increasing R‐ratio in lab air and aqueous solutions is weakly linked to decreasing crack closure behind the crack tip but strongly related to the access of the environment to the crack tip region and its influence on fatigue damage at and ahead of the crack tip. Supporting evidence for this interpretation comes from the lack of ΔKth dependence on R in a good vacuum (with partial pressure of 10−5 Pa or less). In chemical environments, our viewpoint is supported by a critical analysis of corrosion processes that found that there is insufficient time for most metallic species to form ions, hydrolyze, and transform into hard phases at the crack tip before closure. Therefore, when closure occurs at the crack tip, most of the oxidized metallic species will exist as aquo‐complexes, gel, or colloids that have insufficient shear strength to wedge crack faces during unloading.

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Section: Introductionmentioning

confidence: 99%