Crack closure and crack propagation rates in 7050 aluminum

Gan, Dershin; Weertman, J.

doi:10.1016/0013-7944(81)90108-9

Cited by 89 publications

(19 citation statements)

References 10 publications

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“…It is well recognized that variable-amplitude cyclic loading can retard or accelerate the crack propagation rate by making it difficult to predict the crack propagation rate and fatigue life [1][2][3][4][5][6]. A tensile overload, a load higher than a maximum load during constant-amplitude cyclic loading, intervened during constant-amplitude cyclic loading is one of the examples to retard the crack propagation rate and increase the fatigue lifetime significantly.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Strain Evolution around a Crack Tip under Steady- and Overloaded-Fatigue Conditions

Lee

Huang

Woo

et al. 2015

Metals

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Abstract:We investigated the evolution of the strain fields around a fatigued crack tip between the steady-and overloaded-fatigue conditions using a nondestructive neutron diffraction technique. The two fatigued compact-tension specimens, with a different fatigue history but an identical applied stress intensity factor range, were used for the direct comparison of the crack tip stress/strain distributions during in situ loading. While strains behind the crack tip in the steady-fatigued specimen are irrelevant to increasing applied load, the strains behind the crack tip in the overloaded-fatigued specimen evolve significantly under loading, leading to a lower driving force of fatigue crack growth. The results reveal the overload retardation mechanism and the correlation between crack tip stress distribution and fatigue crack growth rate.

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Section: Introductionmentioning

confidence: 99%

Dynamic Strain Evolution around a Crack Tip under Steady- and Overloaded-Fatigue Conditions

Lee

Huang

Woo

et al. 2015

Metals

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“…[1][2][3][4][5][6][7][8][9][10] Neutron diffraction can be used as a unique tool for the bulk crack closure measurement, which facilitates the measurements of bulk strain/stress fields around a crack tip under the applied loads. There are several approaches to determine the crack opening load.…”

Section: A Lattice Strain Evolutionmentioning

confidence: 99%

“…A variety of crack closure measurements have been used to investigate the crack growth retardation mechanisms for structural materials. [1][2][3][4][5][6][7][8][9] However, the various closure measurements between the surface and bulk resulted in different closure levels. [10] In addition, due to a lack of experimental capabilities to measure strain/stress fields within the bulk under the applied load, the relationship between overload and retardation has not been quantitatively established.…”

Section: Introductionmentioning

confidence: 99%

“…[11,12] The deep penetration capability of neutrons enables the nondestructive studies of the bulk crack closure behavior as compared to the surface crack closure phenomena observed using strain gauge. [4] Furthermore, the changes in internal strains can be measured in situ under the applied load using the load frame as a function of the distance from the crack tip. At the same time, the dislocation density can be carried out from the diffraction peak profile analyses.…”

Section: Introductionmentioning

confidence: 99%

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Neutron and X-ray Microbeam Diffraction Studies around a Fatigue-Crack Tip after Overload

Lee

Barabash

Chung

et al. 2008

Metall Mater Trans A

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An in-situ neutron diffraction technique was used to investigate the lattice-strain distributions and plastic deformation around a crack tip after overload. The lattice-strain profiles around a crack tip were measured as a function of the applied load during the tensile loading cycles after overload. Dislocation densities calculated from the diffraction peak broadening were presented as a function of the distance from the crack tip. Furthermore, the crystallographic orientation variations were examined near a crack tip using polychromatic X-ray microdiffraction combined with differential aperture microscopy. Crystallographic tilts are considerably observed beneath the surface around a crack tip, and these are consistent with the high dislocation densities near the crack tip measured by neutron peak broadening.

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“…Figure 6 shows values of V'(R) derived from published U(R) functions for aluminium and titanium alloys [3], and from crack growth rate curves for an aluminium alloy [21] and type 304 stainless steel [ 15,22]. Most of the data are for positive R and show a strong dependence of crack growth rate on stress ratio for R > 0.…”

Section: Quenched and Tempered Steelsmentioning

confidence: 99%

Correlation of Fatigue Crack Growth Rate at Different Stress Ratios for Quenched and Tempered Steels and Other Alloys

Robertson¹

1994

Fatigue Fract Eng Mat Struct

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— Measurements of the effect of stress ratio on the constant amplitude fatigue crack growth rates in four quenched and tempered steels in the Paris regime are reported. This data and published data for other alloys (including lower strength steels and non‐ferrous alloys) are evaluated, and a correlation function suitable for practical fatigue life calculations is derived. In addition to stress intensity factor range and stress ratio, other significant parameters are the yield stress of the material and its thickness. For the four steels on which new measurements were made, the degree of dependence of the crack growth rate on stress ratio may be related to sensitivity to environmental conditions.

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Crack closure and crack propagation rates in 7050 aluminum

Cited by 89 publications

References 10 publications

Dynamic Strain Evolution around a Crack Tip under Steady- and Overloaded-Fatigue Conditions

Dynamic Strain Evolution around a Crack Tip under Steady- and Overloaded-Fatigue Conditions

Neutron and X-ray Microbeam Diffraction Studies around a Fatigue-Crack Tip after Overload

Correlation of Fatigue Crack Growth Rate at Different Stress Ratios for Quenched and Tempered Steels and Other Alloys

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