Fracture mechanics analysis for residual stress and crack closure corrections

Lados, Diana A.; Apelian, Diran; Donald, JK

doi:10.1016/j.ijfatigue.2006.07.002

Cited by 60 publications

(28 citation statements)

References 15 publications

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“…After they coalescence, a high stress intensity factor, which represents the magnitude of the stress field, around a large crack leads to unstable and rapid fatigue crack propagation. The compressive residual stress mitigates the actual applied stress and also causes a crack closure effect [27] [28] when cracks occur at the surface, since the residual stress affects the stress field around the crack tip, i.e., the stress intensity factor [29]. Therefore the stress field near the surface and around the crack tip after crack initiation can be greatly reduced by compressive residual stress.…”

Section: Resultsmentioning

confidence: 99%

Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting

Sato¹,

Takakuwa²,

Nakai³

et al. 2016

MSA

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Although Electron Beam Melting (EBM) is an innovative technology, the fatigue properties of materials manufactured by EBM may be lower than those of casted and wrought materials due to defects and surface roughness. In order to enhance the fatigue life of components or structures manufactured by EBM, a mechanical surface treatment technology, e.g., peening, would be effective because peening introduces high compressive residual stress at the surface which can extend the fatigue life considerably. In the present study, specimens were manufactured by EBM using titanium alloy Ti-6Al-4V powder. Two types of specimens were prepared: as-built and as-machined specimens. Specimens of each type were treated by cavitation peening or shot peening. The fatigue lives of the specimens were evaluated by a plate bending fatigue tester. The residual stress and surface roughness were also evaluated. The results obtained showed that the fatigue strength of as-built specimens can be improved by 21% by cavitation peening or shot peening, and the fatigue life under particular applied stresses can also be extended by 178% by cavitation peening.

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Section: Resultsmentioning

confidence: 99%

Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting

Sato¹,

Takakuwa²,

Nakai³

et al. 2016

MSA

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“…To calculate the real-time applied stress ratio R app shown in Figure 2(b) a crack compliance technique [20] was used to calculate K res , which is the stress intensity caused by residual stress at the crack tip. The technique is derived from linear-elastic fracture mechanics and the final expression for K res is presented in Eq.…”

Section: A Constant K Max Fatigue Crack Growth Testing Resultsmentioning

confidence: 99%

“…The stress intensity change caused by closure, DK cl , was calculated using the adjusted compliance ratio (ACR) technique. [18,20] The ACR technique applies fracture mechanics concepts to calculate the effective stress intensity range experienced at the crack tip after closure corrections. The relationship between DK, DK eff , and DK cl is given in Eq.…”

Section: A Constant K Max Fatigue Crack Growth Testing Resultsmentioning

confidence: 99%

“…To establish appropriate stress intensity factor ranges in the presence of closure, various alternative closure corrective methods have been proposed. [8,18,19] From the proposed methods, the adjusted compliance ratio technique by Donald et al [18] has been found to agree most closely with the fracture mechanics derivation of the effective stress intensity range DK eff , which was developed by Lados et al [20] Studies of crack closure in Al-Si-Mg alloys have been conducted, and roughness-induced closure has been linked to dispersoid content and heat treatment. [9,[11][12][13] A two-parameter approach to classify the fatigue crack growth behavior of materials based on the interdependence of DK and K max was suggested by Vasudevan and Sadananda.…”

Section: Introductionmentioning

confidence: 87%

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Effects of Processing Residual Stresses on Fatigue Crack Growth Behavior of Structural Materials: Experimental Approaches and Microstructural Mechanisms

Lammi

2011

Metall Mater Trans A

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Fatigue crack growth mechanisms of long cracks through fields with low and high residual stresses were investigated for a common structural aluminum alloy, 6061-T61. Bulk processing residual stresses were introduced in the material by quenching during heat treatment. Compact tension (CT) specimens were fatigue crack growth (FCG) tested at varying stress ratios to capture the closure and K max effects. The changes in fatigue crack growth mechanisms at the microstructural scale are correlated to closure, stress ratio, and plasticity, which are all dependent on residual stress. A dual-parameter DK-K max approach, which includes corrections for crack closure and residual stresses, is used uniquely to connect fatigue crack growth mechanisms at the microstructural scale with changes in crack growth rates at various stress ratios for low-and high-residual-stress conditions. The methods and tools proposed in this study can be used to optimize existing materials and processes as well as to develop new materials and processes for FCG limited structural applications.

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“…留応力は，亀裂を閉口させる作用があるため (Lados et al, 2007) Depth profile of the residual stress in duralumin plate treated by shot peening, cavitation peening and hybrid peening. Hybrid peening can introduce compressive residual stress deeper than shot peening.…”

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confidence: 99%

Suppression of fatigue crack propagation of duralumin by hybrid peening

Kokubun

Soyama

2018

Transactions of the JSME (In Japanese)

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Peening is one of the mechanical surface modification techniques, which is used to improve the fatigue strength by the introduction of the compressive residual stress into the surface of specimen. Several peening techniques, such as shot peening, cavitation peening and laser peening have been proposed and demonstrated the improvement of fatigue strength. Mechanical properties on surface modification layer vary with the techniques because of the difference of mechanism of impacts and strain rate. Therefore, it is possible to improve the fatigue strength further by hybrid peening, which is a combination of different peening techniques, due to controlling the mechanical properties on surface modification layer. In this paper, in order to demonstrate the suppression of fatigue crack propagation by hybrid peening combining shot peening and cavitation peening or cavitation peening and laser peening, the fatigue crack propagation in duralumin treated by hybrid peening was investigated, and the crack propagation behavior of the specimen treated by hybrid peening and single peening method was compared. The relationship between the fatigue crack propagation and the mechanical properties was also evaluated. It was revealed that hybrid peening (former process: laser peening, latter process: cavitation peening and former process: cavitation peening, latter process: shot peening) was more effective to suppress the fatigue crack propagation than single peening method and the number of cycle to failure of the specimen treated by hybrid peening was the largest. The new indicator f( R ', HV', Rz', ') =  R ･HV･/Rz combined with four factors i.e. compressive residual stress  R , Vickers hardness HV, full-width at half maximum  and maximum height roughness Rz showed the effect of suppression of fatigue crack propagation by peening. Keywordsの概略図を図 5 に示す．レーザには，パルス幅 5 ns，波長 532 nm，ビーム直径 6 mm，最大繰返し周波数 10 Hz， Depth profile of the residual stress in duralumin plate treated by shot peening, cavitation peening and hybrid peening. Hybrid peening can introduce compressive residual stress deeper than shot peening. Distribution of the residual stress in depth on specimen treated by cavitation peening, laser peening and hybrid peening. Cavitation peening introduce larger compressive residual stress at surface than laser peening. The residual stress at surface of the specimen treated by hybrid peening depends on the latter peening technique.© The Japan Society of Mechanical Engineers Vol. 1983, No. 153 (1983, pp.352-363. Camett, J., Shot peening coverage -the real deal, The Shot Peener, Vol. 21, No. 3 (2007) Vol. 65, No. 637 (1999), pp.1942-1947. 長瀬康男, 泉沢正郎, 山本順一, 疲労限度の結晶粒径依存性に及ぼす予ひずみの影響, 日本機械学会論文集A編, Vol. 55, No. 514 (1989), pp.1247-1254. 西島敏, 疲労試験データの統計的整理, 材料, Vol. 29, No. 316 (1980), pp.24-29. ショットピーニング技術協会, 金属疲労とショットピーニング (2004, 現代工学社． Soyama, H. and Yamada, N., Relieving micro-strain by introducing macro-strain in a polycrystalline metal surface by cavitation

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Fracture mechanics analysis for residual stress and crack closure corrections

Cited by 60 publications

References 15 publications

Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting

Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting

Effects of Processing Residual Stresses on Fatigue Crack Growth Behavior of Structural Materials: Experimental Approaches and Microstructural Mechanisms

Suppression of fatigue crack propagation of duralumin by hybrid peening

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