Full field measurements of anisotropic stress intensity factor ranges in fatigue

Pataky, Garrett J.; Sangid, Michael D.; Şehitoğlu, Hüseyin; Hamilton, Reginald F.; Maier, Hans Jürgen; Sofronis, Petros

doi:10.1016/j.engfracmech.2012.06.002

Cited by 48 publications

(18 citation statements)

References 36 publications

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“…A nonlinear least‐squares regression can be used to determine effective stress intensity factor ranges and how they change during a load cycle. The procedure described by Pataky et al . is adopted.…”

Section: Methodsmentioning

confidence: 99%

“…extracted both ΔK I and ΔK II during mixed‐mode propagation. Recently, DIC was successfully applied to analyse fatigue crack growth in 316 L steel single crystals and to study crack propagation both at room and at high temperature in Haynes 230 polycrystals . An important aspect of these techniques was that, because they were applied on experimental displacements, they included plasticity induced crack closure, allowing for the determination of the effective stress intensity factor range (Δ K eff ) .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fatigue crack growth in Haynes 230 single crystals: an analysis with digital image correlation

Rabbolini

Pataky

Şehitoğlu

et al. 2014

Fatigue Fract Eng Mat Struct

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A B S T R A C T Fatigue crack growth was investigated in Haynes 230, a nickel-based superalloy. Anisotropic stress intensity factors were calculated with a least squares algorithm using the displacements obtained from digital image correlation. Crack opening/sliding levels were measured by analysing the relative displacement of crack flanks. Reversed crack tip plastic zones were calculated adopting an anisotropic yield criterion. The strains measured in the reversed plastic zone by digital image correlation showed a dependence on crystallographic orientation. Finally, a finite element model was adopted to examine plasticity around the crack tip. Results were compared with the experimentally observed strains.Keywords effective stress intensity factor range; fatigue crack growth; mixed-mode propagation; plastic zone; single crystal nickel-based alloy; single crystal plasticity. N O M E N C L A T U R Ea ij = Elastic constants A = Rigid body rotation B u = Horizontal rigid body translation B v = Vertical rigid body translation C = Paris law coefficient g = Slip system strength h 0 = Slip system initial hardening modulus h aβ = Single crystal hardening matrix K I = Mode I stress intensity factor K II = Mode II stress intensity factor n = Paris law exponent q = Latent hardening coefficient r = Radial distance from crack tip R = Load ratio S = Yield stress in the shear direction (Hill's criterion) t = ratio between ΔK II and ΔK I T = T-stress term u = Horizontal displacements v = Vertical displacements X, Y, Z = Yield stress in the principal directions (Hill's criterion) z = Rate sensitivity exponent α = Energy release rate ratio factor γ = Shear strain ΔK I = Mode I stress intensity factor range ΔK II = Mode II stress intensity factor range ΔK I,eff = Mode I effective stress intensity factor range ΔK II,eff = Mode II effective stress intensity factor range ΔK tot = Combined stress intensity factor range Correspondence: S. Rabbolini.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fatigue crack growth in Haynes 230 single crystals: an analysis with digital image correlation

Rabbolini

Pataky

Şehitoğlu

et al. 2014

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

“…Moreover, taking several pictures of the defect during a load cycle, is it possible to evaluate the evolution of ∆K eff and to calculate crack opening levels. In this work, the procedure discussed in [7][8][9]11] is adopted. Since no mode II sliding was observed, since the crack propagated in a plane perpendicular to the loading direction, only ∆K I was considered in the calculations.…”

Section: Crack Closure Measurements Based On Full Field Regressionmentioning

confidence: 99%

Multi-scale crack closure measurements with digital image correlation on Haynes 230

Beretta¹,

Rabbolini²,

Bello³

2015

Frattura Ed Integrità Strutturale

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ABSTRACT. An experimental campaign was developed to study fatigue crack growth in Haynes 230, a Ni-based superalloy. The effects of crack closure were investigated with digital image correlation, by applying two different approaches. Initially, full field regression algorithms were applied to extract the effective stress intensity factor ranges from the singular displacement field measured at crack tips. Local closure measurements were then performed by considering crack flanks relative displacements. Two points virtual extensometers were applied in this phase. Experimental results were then compared to the reference da/dN -∆K eff curve: it was found that the correct estimation of crack opening levels shifts all the experimental points on the reference curve, showing that DIC can be successfully applied to measure crack closure effects.

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“…In the research community, DIC has been extensively used to measure real-time (in situ) strain fields for different applications such as slip/twin nucleation, fatigue damage initiation and crack closure measurements [16][17][18][19]. For these applications, the typical image resolution is approximately 1-2 μm/px.…”

Section: Philosophical Magazine 2555mentioning

confidence: 99%

Shape memory behavior in Fe₃Al-modeling and experiments

Ojha

Alkan

Patriarca

et al. 2015

Philosophical Magazine

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The Fe 3 Al alloy with D0 3 structure exhibits large recoverable strains due to reversible slips. Tension and compression experiments were conducted on single crystals of Fe 3 Al, and the onset of slip in forward and reverse directions were obtained utilizing high-resolution digital image correlation technique. The back stress provides the driving force for reversal of deformation upon unloading, resulting in a superelastic phenomenon as in shape memory alloys. Using density functional theory simulations, we obtain the energy barriers (GSFE -generalized stacking fault energy) for {1 1 0}〈1 1 1〉 and {1 1 2} 〈1 1 1〉 slips in D0 3 Fe 3 Al and the elastic moduli tensor, and undertake anisotropic continuum calculations to obtain the back stress and the frictional stress responsible for reversible slip. We compare the theoretically obtained slip stress magnitudes (friction and back stress) with the experimental measurements disclosing excellent agreement.

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Full field measurements of anisotropic stress intensity factor ranges in fatigue

Cited by 48 publications

References 36 publications

Fatigue crack growth in Haynes 230 single crystals: an analysis with digital image correlation

Fatigue crack growth in Haynes 230 single crystals: an analysis with digital image correlation

Multi-scale crack closure measurements with digital image correlation on Haynes 230

Shape memory behavior in Fe₃Al-modeling and experiments

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Full field measurements of anisotropic stress intensity factor ranges in fatigue

Cited by 48 publications

References 36 publications

Fatigue crack growth in Haynes 230 single crystals: an analysis with digital image correlation

Fatigue crack growth in Haynes 230 single crystals: an analysis with digital image correlation

Multi-scale crack closure measurements with digital image correlation on Haynes 230

Shape memory behavior in Fe3Al-modeling and experiments

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Product

Resources

About

Shape memory behavior in Fe₃Al-modeling and experiments