Hybrid discrete dislocation models for fatigue crack growth

Deshpande, V.S.; Needleman, A.; Giessen, E. van der; Wallin, Mathias

doi:10.1016/j.ijfatigue.2009.10.015

Cited by 28 publications

(10 citation statements)

References 31 publications

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“…Recent examples in the literature using discrete dislocation modelling to study the threshold conditions for fatigue crack growth include the work of Deshpande et al [8], Pippan [9] and Wilkinson et al [10]. Curtin et al [11] developed a hybrid discrete dislocation plasticity (DDP) model for fatigue crack growth by introducing a cohesive surface constitutive relation, implying that crack initiation and growth are driven by local stresses. Brinckmann and van der Giessen [12] developed a DDP fatigue crack initiation model that incorporates surface roughness and cohesive surfaces to model near-atomic separation leading to fracture.…”

Section: Introductionmentioning

confidence: 99%

The dislocation configurational energy density in discrete dislocation plasticity

Zheng

Prastiti

Balint

et al. 2019

Journal of the Mechanics and Physics of Solids

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Section: Introductionmentioning

confidence: 99%

The dislocation configurational energy density in discrete dislocation plasticity

Zheng

Prastiti

Balint

et al. 2019

Journal of the Mechanics and Physics of Solids

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“…Therefore, it is necessary to consider the fatigue process at all scales. A scale‐dependent physics‐based model is required for accurate simulation and understanding of material behaviour in various operational environments to assess fatigue life of a structure …”

Section: Introductionmentioning

confidence: 99%

“…A scale-dependent physics-based model is required for accurate simulation and understanding of material behaviour in various operational environments to assess fatigue life of a structure. [1][2][3][4][5] The process of fatigue failure of mechanical components may be divided into the following stages: (1) crack nucleation, (2) small crack growth, (3) long crack growth and (4) occurrence of final failure. In engineering applications, the first two stages are usually termed as the 'crack initiation or small crack formation period' while long crack growth is termed as the 'crack propagation period'.…”

Section: Introductionmentioning

confidence: 99%

Multiscale fatigue crack growth modelling for welded stiffened panels

Božić

Schmauder

Mlikota

et al. 2014

Fatigue Fract Eng Mat Struct

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A B S T R A C T The influence of welding residual stresses in stiffened panels on effective stress intensity factor (SIF) values and fatigue crack growth rate is studied in this paper. Interpretation of relevant effects on different length scales such as dislocation appearance and microstructural crack nucleation and propagation is taken into account using molecular dynamics simulations as well as a Tanaka-Mura approach for the analysis of the problem. Mode I SIFs, K I , were calculated by the finite element method using shell elements and the crack tip displacement extrapolation technique. The total SIF value, K tot , is derived by a part due to the applied load, K appl , and by a part due to welding residual stresses, K res . Fatigue crack propagation simulations based on power law models showed that high tensile residual stresses in the vicinity of a stiffener significantly increase the crack growth rate, which is in good agreement with experimental results.Keywords dislocation; fatigue crack growth rate; microstructurally small cracks; residual stress. N O M E N C L A T U R Ea = half crack length a 0 = initial crack length a fin = final crack length C = material constant of the Paris equation CRSS = critical resolved shear stress d = slip band length da/dN = crack growth rate E = Young's modulus F → r; t ð Þ = interatomic force F max = maximum applied force F min = minimum applied force G = shear modulus K = stress intensity factor (SIF) K appl = stress intensity factor due to the applied load K res = stress intensity factor due to weld residual stresses K th = stress intensity factor threshold K tot = total stress intensity factor m = atomic mass m = material constant of the Paris equation N = number of stress cycles for the fatigue crack propagation N f = number of stress cycles for fatigue failure N g = number of stress cycles required for crack nucleation in a single grain N ini = number of stress cycles needed for the initiation of a small crack R = stress ratio R eff = effective stress intensity factor ratio U → r ; t ð Þ = interatomic embedded atom method pair potential W c = specific fracture energy per unit area Correspondence: Ž. Božić.

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“…However, it does not use of discrete dislocations concept. Several simulations using the discrete nature of dislocations have been done before [18,[21][22][23][24][25][26][27][28][29][30][31][32][33][34], which suggest that the fatigue threshold behavior can be related to the discrete nature of plastic deformation.…”

Section: Crack-dislocation Interaction(s)mentioning

confidence: 99%

Dislocation Emission and Crack Dislocation Interactions

Pande

Goswami

2020

Metals

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An understanding of the crack initiation and crack growth in metals spanning the entire spectrum of conventional and advanced has long been a major scientific challenge. It is known that dislocations are involved both in the initiation and propagation of cracks in metals and alloys. In this review, we first describe the experimental observations of dislocation emission from cracks under stress. Then the role played by these dislocations in fatigue and fracture is considered at a fundamental level by considering the interactions of crack and dislocations emitted from the crack. We obtain precise expression for the equilibrium positions of dislocations in an array ahead of crack tip. We estimate important parameters, such as plastic zone size, dislocation free zone and dislocation stress intensity factor for the analysis of crack propagation. Finally, we describe very recent novel and significant results, such as residual stresses and relatively large lattice rotations across a number of grains in front of the crack that accompanies fatigue process.

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Hybrid discrete dislocation models for fatigue crack growth

Abstract: Hybrid discrete dislocation models for fatigue crack growth Curtin, W. A.; Deshpande, V. S.; Needleman, A.; Van der Giessen, E.; Wallin, M.

Cited by 28 publications

References 31 publications

The dislocation configurational energy density in discrete dislocation plasticity

The dislocation configurational energy density in discrete dislocation plasticity

Multiscale fatigue crack growth modelling for welded stiffened panels

Dislocation Emission and Crack Dislocation Interactions

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