Microstructure-sensitive weighted probability approach for modeling surface to bulk transition of high cycle fatigue failures dominated by primary inclusions

Salajegheh, Nima

doi:10.1016/j.ijfatigue.2013.08.025

Cited by 23 publications

(30 citation statements)

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“…Inspired by Pineau's early works on probabilistic fatigue associated with microstructure effects near the surface and at notches [105,106], Salajegheh and McDowell [107] introduced a probabilistic strategy to model the transition from surface to bulk of HCF crack formation promoted by the interaction of debonded primary inclusions with microstructure in IN 100 Ni-base superalloy. Prasannavenkatesan and co-workers [1,2] considered the effect of shot peening-induced surface residual stresses, pores, and hard and soft primary inclusions in martensitic gear steel in the context of 3D polycrystal plasticity and nonlocal FIPs.…”

Section: Probabilistic Approaches To Account For Coupled Notchmicrostmentioning

confidence: 99%

Failure of metals II: Fatigue

Pineau¹,

McDowell²,

Busso³

et al. 2016

Acta Materialia

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234

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Section: Probabilistic Approaches To Account For Coupled Notchmicrostmentioning

confidence: 99%

Failure of metals II: Fatigue

Pineau¹,

McDowell²,

Busso³

et al. 2016

Acta Materialia

Self Cite

234

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“…Subsurface crack formation often occurs at discontinuities such as voids, inclusions or secondary phases, with much lower influence of the environment [7]. Whether a crack will fail from a surface or subsurface initiation site is therefore related to both the probability of occurrence of microstructure discontinuities at and below the surface and the degree to which the environment enhances surface crack propagation [8].…”

Section: Interpretation Of Damage Mechanisms In the Hcf And Vhcf Regimesmentioning

confidence: 99%

“…In these cases, the driving force should be evaluated in terms of the local gradient of plastic ranges (e.g., the domain with the highest driving force) and updated according to the crack path. For example, the driving force of a partially debonded inclusion can be assessed by computing FIPs along the vicinity of the debonded perimeter [8]. The analysis of this perimeter smoothes out local variability, yielding values amenable for comparison with experimental data such as beach marks.…”

Section: Mesoscale Driving Forces For Hcf and Vhcfmentioning

confidence: 99%

“…Clearly, relation (8) employs the coarse scale FIP as a surrogate driving force parameter that is intended to parameterize the dependence of the fine scale propagation relation on DCTD (DCTD ¼…”

Section: Dominant Hierarchy In Hcf and Vhcf Regimesmentioning

confidence: 99%

“…In Eq. (8), an equivalence of the coarse scale relation is implied to a fine scale relation in the crack tip process zone via the second equality, where / is an irreversibility factor that controls cyclic crack advance associated with the fraction of process zone dislocations that do not return to the crack tip during unloading [65].…”

Section: Dominant Hierarchy In Hcf and Vhcf Regimesmentioning

confidence: 99%

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Computational micromechanics of fatigue of microstructures in the HCF–VHCF regimes

Musinski

2016

International Journal of Fatigue

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a b s t r a c tAdvances in higher resolution experimental techniques have shown that metallic materials can develop fatigue cracks under cyclic loading levels significantly below the yield stress. Indeed, the traditional notion of a fatigue limit can be recast in terms of limits associated with nucleation and arrest of fatigue cracks at the microstructural scale. Although fatigue damage characteristically emerges from irreversible dislocation processes at sub-grain scales, the specific microstructure attributes, environment, and loading conditions can strongly affect the apparent failure mode and surface to subsurface transitions. In this paper we discuss multiple mechanisms that occur during fatigue loading in the high cycle fatigue (HCF) to very high cycle fatigue (VHCF) regimes. We compare these regimes, focusing on strategies to bridge experimental and modeling approaches exercised at multiple length scales and discussing particular challenges to modeling and simulation regarding microstructure-sensitive fatigue driving forces and thresholds. We conclude by discussing some of the challenges in predicting the transition of failure mechanisms at different stress and strain amplitudes.

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Generalised Voronoi tessellation for generating microstructural finite element models with controllable grain-size distributions and grain aspect ratios

Shen

Proust

2015

Int. J. Numer. Meth. Engng

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A generalised Voronoi tessellation is proposed to create three-dimensional microstructural finite element model, which can effectively reproduce the grain size distribution and grain aspect ratio obtained from experiments. This new approach consists of two steps. The first step generates the desired lognormal grain size distribution with a given average grain volume and standard deviation. The second step requires grouping meshed elements to create a specific grain aspect ratio, using the Voronoi generators from the first step. A new concept is introduced to describe the transition from the Poisson-Voronoi tessellation to the centroidal Voronoi tessellation. More importantly, instead of using the conventional way where the Voronoi cells are first generated and then meshed into finite elements, this new approach discretises the pre-meshed specimen with the Voronoi generators. This new technique prevents the presence of high density mesh at the vertices of Voronoi cells, and can tessellate irregular geometry much more easily. Examples of microstructures with different size distributions, non-equiaxed grains and complicated specimen geometries further demonstrate that the proposed approach can offer great flexibility to model various specimen geometries while keeping the process simple and efficient. GENERALISED VORONOI TESSELLATION FOR GENERATING MICROSTRUCTURES 145 polycrystals. Its effectiveness and robustness have been verified for CPFE applications in terms of nanoindentation, fatigue, grain size and grain boundary effects and twinning [7][8][9][10][11]. Kumar et al. [12] studied the properties of 3D Poisson-Voronoi cells in terms of the distributions of the number of cell faces, volume and surface area. They numerically simulated several hundred thousand cells using the Monte Carlo method and found that the faces, volume and surface area distributions of the Poisson-Voronoi cells can be best described by a two-parameter gamma distribution. Nonetheless, if the number of cells is less than several thousands, a lognormal distribution can also be used to approximate these distributions. In terms of grain volume, intersected area and intercept length in a polycrystal, Vaz and Fortes [13] concluded that these properties are usually lognormally distributed. Their experimental results have shown that the gamma and lognormal distributions can describe the sizes of metallic polycrystals fairly well. Furthermore, it was revealed that the distributions of different dimensions, that is cell volumes in 3D, cell areas in 2D and edge lengths in 1D, have to be fitted with different parameters of distribution [14]. Hence, in order to accurately study a 3D microstructure involving the grain size distribution using CPFE simulations, a 3D VT that reflects the specific grain size distribution is required. The lognormal distribution function was also used to study elastic-viscoplastic materials through a representative volume element [15]. Recently, Lazar et al. [16] analysed a structure containing 250 million Poisson-Voronoi cell...

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Microstructure-sensitive weighted probability approach for modeling surface to bulk transition of high cycle fatigue failures dominated by primary inclusions

Cited by 23 publications

References 50 publications

Failure of metals II: Fatigue

Failure of metals II: Fatigue

Computational micromechanics of fatigue of microstructures in the HCF–VHCF regimes

Generalised Voronoi tessellation for generating microstructural finite element models with controllable grain-size distributions and grain aspect ratios

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