Dislocation Modelling of Fatigue Cracks: An Overview

Riemelmoser, F. O.; Gumbsch, Peter; Pippan, Reinhard

doi:10.2320/matertrans.42.2

Cited by 70 publications

(34 citation statements)

References 37 publications

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“…Figure 5a reveals that ⌬K th is insensitive to the load ratio for RϾ0. 3. Below this value of R the fatigue threshold increases with decreasing values of R.…”

Section: Fatigue With a Reversible Cohesive Lawmentioning

confidence: 88%

“…As a consequence, for crystalline metals, the discreteness of dislocations comes into play. The literature on dislocation models for fatigue crack growth has recently been reviewed by Riemelmoser et al [3]. In particular, discrete dislocation models of threshold conditions for fatigue crack growth have been proposed by Pippan and co-workers [4][5][6] and Wilkinson et al [7].…”

Section: Introductionmentioning

confidence: 99%

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A discrete dislocation analysis of near-threshold fatigue crack growth

2001

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A discrete dislocation analysis of near-threshold fatigue crack growth Deshpande, V.S.; Needleman, A.; van der Giessen, E. Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Deshpande, V. S., . A discrete dislocation analysis of nearthreshold fatigue crack growth. Acta Materialia, 49(16), 3189 -3203. https://doi.org/10.1016/S1359-6454(01)00220-8 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Abstract-Analyses of cyclic loading of a plane strain mode I crack under small-scale yielding are carried out using discrete dislocation dynamics. The formulation is the same as used to analyze crack growth under monotonic loading conditions, differing only in the remote stress intensity factor being a cyclic function of time. The dislocations are all of edge character and are modeled as line singularities in an elastic solid. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation are incorporated into the formulation through a set of constitutive rules. Either reversible or irreversible relations are specified between the opening traction and the displacement jump across a cohesive surface ahead of the initial crack tip in order to simulate cyclic loading as could occur in a vacuum or in an oxidizing environment, respectively. In accord with experimental data we find that the fatigue threshold ⌬K th is weakly dependent on the load ratio R when the reversible cohesive surface is employed. This intrinsic dependence of the threshold on R is an outcome of source limited plasticity at low R values and plastic shakedown at higher R values. On the other hand, ⌬K th is seen to decrease approximately linearly with increasing R followed by a plateau when the irreversible cohesive law is used. Our simulations show that in this case the fatigue threshold is dominated by crack closure at low values of R. Calculations illustrating the effects of obstacle density, tensile overloads and slip geometry on cyclic crack growth behavior are also presented. 

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“…Figure 5a reveals that ⌬K th is insensitive to the load ratio for RϾ0. 3. Below this value of R the fatigue threshold increases with decreasing values of R.…”

Section: Fatigue With a Reversible Cohesive Lawmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

A discrete dislocation analysis of near-threshold fatigue crack growth

2001

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“…Recent literature on dislocation models for fatigue crack growth has been reviewed by Riemelmoser et al [14]. These dislocation models, by for example Pippan and co-workers [15][16][17] and Wilkinson et al [18], are meant to represent the deformation-controlled fatigue crack growth mechanism proposed by Laird and Smith [8] and Neumann [19].…”

Section: Introductionmentioning

confidence: 99%

Discrete dislocation modeling of fatigue crack propagation

Deshpande

Needleman

Giessen³

2002

Acta Materialia

128

100

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Discrete dislocation modeling of fatigue crack propagation Deshpande, V.S.; Needleman, A.; van der Giessen, E.Published in: Acta Materialia DOI: 10.1016/S1359-6454(01)00377-9IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document VersionPublisher's PDF, also known as Version of record Publication date: 2002Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Deshpande, V. S., Needleman, A., & van der Giessen, E. (2002). Discrete dislocation modeling of fatigue crack propagation. Acta Materialia, 50(4), 831-846. [PII S1359-6454(01)00377-9]. https://doi.org/10.1016/S1359-6454(01)00377-9 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractAnalyses of the growth of a plane strain crack subject to remote mode I cyclic loading under small-scale yielding are carried out using discrete dislocation dynamics. Cracks along a metal-rigid substrate interface and in a single crystal are studied. The formulation is the same as that used to analyze crack growth under monotonic loading conditions, differing only in the remote stress intensity factor being a cyclic function of time. Plastic deformation is modeled through the motion of edge dislocations in an elastic solid with the lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation being incorporated through a set of constitutive rules. An irreversible relation is specified between the opening traction and the displacement jump across a cohesive surface ahead of the initial crack tip in order to simulate cyclic loading in an oxidizing environment. The cyclic crack growth rate log(da/dN) versus applied stress intensity factor range log(⌬K I ) curve that emerges naturally from the solution of the boundary value problem shows distinct threshold and Paris law regimes. Paris law exponents in the range 4 to 8 are obtained for the parameters employed here. Furthermore, rather uniformly spaced slip bands corresponding to surface striations develop in the wakes of the propagating cracks. 

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“…Literature on dislocation models for fatigue has been reviewed by Riemelmoser et al [16]. Dislocation models by Pippan et al [17][18][19] and Wilkinson et al [20], are meant to represent the deformation-controlled fatigue crack growth mechanism proposed by Laird and Smith [10] and Neumann [21].…”

Section: Introductionmentioning

confidence: 99%

Scaling of discrete dislocation predictions for near-threshold fatigue crack growth

2003

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Analyses of the growth of a plane strain crack subject to remote mode I cyclic loading under small scale yielding are carried out using discrete dislocation dynamics. Plastic deformation is modelled through the motion of edge dislocations in an elastic solid with the lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation being incorporated through a set of constitutive rules. An irreversible relation is specified between the opening traction and the displacement jump across a cohesive surface ahead of the initial crack tip in order to simulate cyclic loading in an oxidizing environment. Calculations are carried out with different material parameters so that values of yield strength, cohesive strength and elastic moduli varying by factors of three to four are considered. The fatigue crack growth predictions are found to be insensitive to the yield strength of the material despite the number of dislocations and the plastic zone size varying by approximately an order of magnitude. The fatigue threshold scales with the fracture toughness of the purely elastic solid, with the experimentally observed linear scaling with Young's modulus an outcome when the cohesive strength scales with Young's modulus.

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Dislocation Modelling of Fatigue Cracks: An Overview

Cited by 70 publications

References 37 publications

A discrete dislocation analysis of near-threshold fatigue crack growth

A discrete dislocation analysis of near-threshold fatigue crack growth

Discrete dislocation modeling of fatigue crack propagation

Scaling of discrete dislocation predictions for near-threshold fatigue crack growth

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