High resolution digital image correlation measurements of strain accumulation in fatigue crack growth

Carroll, Jay; Abuzaid, Wael; Lambros, John; Şehitoğlu, Hüseyin

doi:10.1016/j.ijfatigue.2012.06.010

Cited by 190 publications

(115 citation statements)

References 49 publications

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“…Such features developing over many neighbouring grains are not well captured by conventional methods such as TEM or X-ray and neutron diffraction. However, DIC observations (Carroll et al, 2013;Littlewood and Wilkinson, 2012b) and the resulting longer length scale patterning of dislocation density revealed here by HR-EBSD suggest that the sphere of influence of a particular grain on the overall pattern of deformation may extend a considerable distance. This may have significant implications for the volumes of material that must be simulated to avoid the deformation patterns being dominated by the boundary conditions imposed on the system.…”

Section: Discussionmentioning

confidence: 74%

The orientation and strain dependence of dislocation structure evolution in monotonically deformed polycrystalline copper

Jiang

Britton

Wilkinson

2015

International Journal of Plasticity

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Section: Discussionmentioning

confidence: 74%

The orientation and strain dependence of dislocation structure evolution in monotonically deformed polycrystalline copper

Jiang

Britton

Wilkinson

2015

International Journal of Plasticity

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“…To further progress and develop the next generation of alloys, a greater understanding of polycrystalline materials at the microstructural scale must be addressed. It is well accepted that crystallography, morphology and interface constraints contribute to the heterogeneity in local stress, strain and dislocation density witnessed across grains [1][2][3][4], and much of the heterogeneity arises from anisotropic slip activity.…”

Section: Introductionmentioning

confidence: 99%

An HR-EBSD and computational crystal plasticity investigation of microstructural stress distributions and fatigue hotspots in polycrystalline copper

et al. 2016

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High resolution EBSD studies on a deformed copper polycrystal have been carried out to quantify the microstructural residual stress distributions, and those of stress state including triaxiality of importance in defect nucleation studies. Crystal plasticity analysis of a representative, similarly textured, model polycrystal has been carried out showing that the experimental distributions of microstructural residual stress components, effective stress, hydrostatic stress and stress triaxiality are well captured.The crystal model enables point-wise microstructural Schmid factors to be calculated both globally (ie with respect to the macroscopic remote loading) and locally from full knowledge of the grain-level stress state. Significant differences are demonstrated such that global Schmid analysis tends to overestimate slip activity and the frequency of high Schmid factors, indicating that the local microstructural heterogeneity is significant and caution is necessary in interpreting polycrystal behaviour using global Schmid factors. A stored energy criterion for fatigue crack nucleation indicates that preferential sites for fatigue crack nucleation are local to grain boundaries (as opposed to triple junctions), and that hard-soft grain interfaces where high GND densities develop are preferable.

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“…The strain mapping based on DIC was already utilized by several authors to describe the strain field around cracks. The DIC methods that do not address the crack discontinuity directly (Ref [17][18][19] can be characterized as continuous DIC methods. In these methods, the crack is detected by thresholding the deformation field.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Crack Growth in Bodies with Thermally Sprayed Coating

et al. 2015

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Many applications of thermally sprayed coatings call for increased fatigue resistance of coated parts. Despite the intensive research in this area, the influence of coating on fatigue is still not completely understood. In this paper, the localization of crack initiation sites and the dynamics of crack propagation are studied. The resonance bending fatigue test was employed to test flat specimens with both sides coated. Hastelloy-X substrates coated with classical thermal barrier coating consisting of yttria stabilized zirconia and NiCoCrAlY layers. The strain distribution on the coating surface was evaluated by the Digital Image Correlation method through the whole duration of the fatigue test. Localization of crack initiation sites and the mode of crack propagation in the coated specimen are related to the observed resonance frequency. The individual phases of specimen degradation, i.e., the changes of material properties, crack initiation, and crack propagation, were identified. The tested coatings strongly influenced the first two phases, and the influence on the crack propagation was less significant. In general, the presented crack detection method can be used as a sensitive nondestructive testing method well suited for coated parts.

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High resolution digital image correlation measurements of strain accumulation in fatigue crack growth

Cited by 190 publications

References 49 publications

The orientation and strain dependence of dislocation structure evolution in monotonically deformed polycrystalline copper

The orientation and strain dependence of dislocation structure evolution in monotonically deformed polycrystalline copper

An HR-EBSD and computational crystal plasticity investigation of microstructural stress distributions and fatigue hotspots in polycrystalline copper

Fatigue Crack Growth in Bodies with Thermally Sprayed Coating

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