On the behaviour of small fatigue cracks emanating from corrosion pits: Part I – The influence of mechanical factors

Fatoba, Olusegun; Akid, Robert

doi:10.1016/j.tafmec.2021.103154

Cited by 23 publications

(16 citation statements)

References 42 publications

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“…Afterwards, the specimens were cleaned, and the depth and width of the corrosion pits were measured using a confocal laser scanning microscope (CLSM). The results demonstrating the good repeatability of the pitting procedure have been reported elsewhere 46 …”

Section: Methodssupporting

confidence: 66%

“…To understand the relative influence of proximity on crack initiation and consequently fatigue resistance, the results from the present study are compared with those previously reported for SPs that were tested under similar loading conditions 46 . The

N_{i}

versus separation distance results for different pit sizes at

∆ σ

= 405, 427.5, and 450 MPa are presented in Figures 3A–C, respectively.…”

Section: Resultsmentioning

confidence: 95%

“…Therefore for this study, two groups of 200 and 270 μm deep pits with varying separation distances were employed; see Table 2. The two pit depths were selected based on availability of baseline test data obtained for SPs with same depths in an earlier investigation 46 . Moreover, the depths and aspect ratios are representative of those observed under service conditions as shown by macroscopic analysis of corrosion pits found on an out‐of‐service oil well downhole pipe by Evans 20 .…”

Section: Methodsmentioning

confidence: 99%

“…Due to symmetry, only half of the fatigue specimen was modeled. From a mesh convergence study, element size of 10 and 100 μm was established for the finer and coarse mesh regions 46 . 3‐D 20‐node quadratic hexahedral with reduced integration (C3D20R) and10‐node quadratic tetrahedral (C3D10) solid continuum elements were, respectively, used in the finer and coarse regions of the model, respectively.…”

Section: Numerical Modelingmentioning

confidence: 99%

“…In an earlier study, 46 the authors investigated in an air environment the effects of pit depth and aspect ratio on the pit‐to‐crack transition behavior by conducting fatigue tests on steel specimens containing “single pits” that were generated electrochemically. Their findings showed that crack initiation lifetimes, fatigue lifetimes, and fatigue endurance decreased with increasing pit depth and aspect ratio.…”

Section: Introductionmentioning

confidence: 99%

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The influence of corrosion pit–pit spacing on the pit‐to‐crack transition and fatigue lifetime

Fatoba

Akid

2022

Fatigue Fract Eng Mat Struct

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The influence of separation distance between pre-induced corrosion pits on both crack initiation and fatigue lifetimes is studied in an air environment by testing specimens containing pit pairs in the low-stress, high cycle fatigue regime. The results of these tests are compared with equivalent tests with samples containing similar sized single pit. Within the scope of pit sizes and separation distances investigated, when the separation distance is below a threshold, decreasing the separation distance between pits leads to earlier onset of crack initiation and decreased fatigue lifetimes; this threshold being dependent on the applied stress and relative pit sizes. When the separation distance is above this threshold, multiple pits tend to behave independently of each other. The implication of the results from the viewpoint of structural integrity assessment of components containing flaws such as corrosion pits in close proximity is discussed.

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Section: Methodssupporting

confidence: 66%

N_{i}

versus separation distance results for different pit sizes at

∆ σ

= 405, 427.5, and 450 MPa are presented in Figures 3A–C, respectively.…”

Section: Resultsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Numerical Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of corrosion pit–pit spacing on the pit‐to‐crack transition and fatigue lifetime

Fatoba

Akid

2022

Fatigue Fract Eng Mat Struct

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Extension of the a posteriori finite element method (APFEM) to geometrical alterations and application to stochastic homogenisation

Ammouche,

Jérusalem

2024

Numerical Meth Engineering

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We recently proposed an efficient method facilitating the parametric study of a finite element mechanical simulation as a postprocessing step, that is, without the need to run multiple simulations: the a posteriori finite element method (APFEM). APFEM only requires the knowledge of the vertices of the parameter space and is able to predict accurately how the degrees of freedom of a simulation, i.e., nodal displacements, and other outputs of interests, for example, element stress tensors, evolve when simulation parameters vary within their predefined ranges. In our previous work, these parameters were restricted to material properties and loading conditions. Here, we extend the APFEM to additionally account for changes in the original geometry. This is achieved by defining an intermediary reference frame whose mapping is defined stochastically in the weak form. Subsequent deformation is then reached by correcting for this stochastic variation in the reference frame through multiplicative decomposition of the deformation gradient tensor. The resulting framework is shown here to provide accurate mechanical predictions for relevant applications of increasing complexity: (i) quantifying the stress concentration factor of a plate under uniaxial loading with one and two elliptical holes of varying eccentricities, and (ii) performing the stochastic homogenisation of a composite plate with uncertain mechanical properties and geometry inclusion. This extension of APFEM completes our original approach to account parametrically for geometrical alterations, in addition to boundary conditions and material properties. The advantages of this approach in our original work in terms of stochastic prediction, uncertainty quantification, structural and material optimisation and Bayesian inferences are all naturally conserved.

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Environmental assisted cracking and strength attenuation effect computing on the mechanical properties of casing steel P110 for industrial revolution 5.0 applications in sour well environments

et al. 2022

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On the behaviour of small fatigue cracks emanating from corrosion pits: Part I – The influence of mechanical factors

Cited by 23 publications

References 42 publications

The influence of corrosion pit–pit spacing on the pit‐to‐crack transition and fatigue lifetime

The influence of corrosion pit–pit spacing on the pit‐to‐crack transition and fatigue lifetime

Extension of the a posteriori finite element method (APFEM) to geometrical alterations and application to stochastic homogenisation

Environmental assisted cracking and strength attenuation effect computing on the mechanical properties of casing steel P110 for industrial revolution 5.0 applications in sour well environments

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