Effect of Laser Peening Process Parameters and Sequences on Residual Stress Profiles

Kallien, Zina; Keller, Sören; Ventzke, Volker; Kashaev, Nikolai; Klusemann, Benjamin

doi:10.3390/met9060655

Cited by 30 publications

(19 citation statements)

References 24 publications

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“…However, there a noticeable difference between the residual stresses obtained in the longitudinal direction ( σ xx ) and the transverse direction ( σ yy ). The nonequibiaxiality in residual stress profiles could be attributed to the LSP treatment sequence and/or material texture, as observed for the LSP treatment of other high‐strength Al‐alloys as well 50,51 . Close to the specimen's surface, the absolute value of compressive residual stresses in the longitudinal direction is approximately 250 MPa, which refers to approximately 70% of the yield strength of the base material (approximately 350 MPa) 40 .…”

Section: Resultsmentioning

confidence: 74%

On the application of laser shock peening for retardation of surface fatigue cracks in laser beam‐welded AA6056

Kashaev

Ushmaev

Ventzke

et al. 2020

Fatigue Fract Eng Mat Struct

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The present study aims to investigate the extent to which the fatigue behaviour of laser beam-welded AA6056-T6 butt joints with an already existing crack can be improved through the application of laser shock peening. Ultrasonic testing was utilized for in situ (nondestructive) measurement of fatigue crack growth during the fatigue test. This procedure allowed the preparation of welded specimens with surface fatigue cracks with a depth of approximately 1.2 mm. The precracked specimens showed a 20% reduction in the fatigue limit compared with specimens without cracks in the as-welded condition. Through the application of laser shock peening on the surfaces of the precracked specimens, it was possible to recover the fatigue life to the level of the specimens tested in the as-welded condition. The results of this study show that laser shock peening is a very promising technique to recover the fatigue life of welded joints with surface cracks, which can be detected by nondestructive testing. K E Y W O R D Saluminium alloys, fatigue crack, laser beam welding, laser shock peening, residual stress, ultrasonic crack tip diffraction

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Section: Resultsmentioning

confidence: 74%

On the application of laser shock peening for retardation of surface fatigue cracks in laser beam‐welded AA6056

Kashaev

Ushmaev

Ventzke

et al. 2020

Fatigue Fract Eng Mat Struct

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“…In the following the LSP treatment, the experimental residual stress determination and the determination of the fatigue crack growth rate are described. The experimental data for specimens with thickness of 4.8 mm are taken from [14] and [18].…”

Section: Methodsmentioning

confidence: 99%

“…Therefore the total stress-strain state (σ , ε) in the model is the sum of the initial state (σ 0 , ε 0,el ) and the stress-strain state caused by the cyclic loading (σ c , ε c ). Hence, the total strain in the fatigue simulation is ε = ε 0,el + ε c (14) as displayed in Fig. 6b.…”

Section: Incorporation Of Residual Stressesmentioning

confidence: 99%

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Phase-field modelling for fatigue crack growth under laser shock peening-induced residual stresses

et al. 2021

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For the fatigue life of thin-walled components, not only fatigue crack initiation, but also crack growth is decisive. The phase-field method for fracture is a powerful tool to simulate arbitrary crack phenomena. Recently, it has been applied to fatigue fracture. Those models pose an alternative to classical fracture-mechanical approaches for fatigue life estimation. In the first part of this paper, the parameters of a phase-field fatigue model are calibrated and its predictions are compared to results of fatigue crack growth experiments of aluminium sheet material. In the second part, compressive residual stresses are introduced into the components with the help of laser shock peening. It is shown that those residual stresses influence the crack growth rate by retarding and accelerating the crack. In order to study these fatigue mechanisms numerically, a simple strategy to incorporate residual stresses in the phase-field fatigue model is presented and tested with experiments. The study shows that the approach can reproduce the effects of the residual stresses on the crack growth rate.

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“…Deep compressive residual stresses were introduced through the entire specimen thickness. The non-equibiaxiality in the residual stress profiles could be due to the sequence of LSP, material texture, and geometry of the analyzed specimen [23]. Near the surface, the absolute value of compressive residual stresses reaches 220 MPa, which corresponds to approximately 67% of the yield strength of AA2024-T3, i.e., 326 MPa [18].…”

Section: Laser Shock Peening and Residual Stress Analysismentioning

confidence: 99%

The Influence of Laser Shock Peening on Fatigue Properties of AA2024-T3 Alloy with a Fastener Hole

Sikhamov

Fomin

Klusemann

et al. 2020

Metals

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The objective of the present study was to estimate the influence of laser shock peening on the fatigue properties of AA2024-T3 specimens with a fastener hole and to investigate the possibility to heal the initial cracks in such specimens. Fatigue cracks of different lengths were introduced in the specimens with a fastener hole before applying laser shock peening. Deep compressive residual stresses, characterized by the hole drilling method, were generated into the specimens by applying laser shock peening on both sides. Subsequently, the specimens were subjected to fatigue tests. The results show that laser shock peening has a positive effect regarding the fatigue life improvement in the specimens with a fastener hole. In addition, laser shock peening leads to a healing effect on fatigue cracks. The efficiency of this effect depends on the initial crack length. The effect of laser shock peening on the fatigue life periods was determined by using resonant frequency graphs.Metals 2020, 10, 495 2 of 13 and fatigue properties of the aluminum alloy LY12-CZ with various interference values (interference value describes how much a mandrel radius is larger than a hole radius), and it was shown that with increasing interference value from 0% to 6%, the fatigue life increases by a factor of six.Another promising way to improve the behavior of fatigue critical components is laser shock peening (LSP) [7]. LSP is a process in which under the influence of laser pulses, mechanical shock waves arise, propagating under the surface of the material [8]. When the peak pressure of waves exceeds the Hugoniot elastic limit (HEL) of the material, plastic deformation occurs, which leads to compressive residual stresses within the material, i.e., near the surface. The subsurface compressive residual stresses are balanced by the stress field within the material or in zones adjacent to the LSP-treated area. In recent years, various studies have been conducted on the effect of LSP on the fatigue properties of different metallic alloys. Ivetic et al. [9] investigated the effect of the sequence of processes (hole introduction and LSP) on the fatigue properties of AA6082-T6 specimens. The experiments showed that the sequence of processes is important for the improvement of the fatigue life. The beneficial effect of LSP is higher if the hole is introduced after LSP. This is linked to the fact that compressive residual stresses in LSP-treated specimen are compensated by tensile residual stresses [3], and in the case of applying LSP after drilling a hole, the magnitude of tensile stresses would be higher, which would lead to a shorter fatigue life. Achintha et al. [10] evaluated the effect of the size of the LSP-treated area on fatigue properties of AA2024-T3 specimens. Two cases were considered: (i) LSP was performed just around the hole, and (ii) LSP was applied across the entire width of the specimen. The results showed that specimens with a smaller treated area around the hole can withstand more loading cycles than specimens peened along the e...

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Effect of Laser Peening Process Parameters and Sequences on Residual Stress Profiles

Cited by 30 publications

References 24 publications

On the application of laser shock peening for retardation of surface fatigue cracks in laser beam‐welded AA6056

On the application of laser shock peening for retardation of surface fatigue cracks in laser beam‐welded AA6056

Phase-field modelling for fatigue crack growth under laser shock peening-induced residual stresses

The Influence of Laser Shock Peening on Fatigue Properties of AA2024-T3 Alloy with a Fastener Hole

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