Fatigue in laser shock peened open-hole thin aluminium specimens

Ivetic, Goran; Meneghin, Ivan; Troiani, Enrico; Molinari, G.; Ocaña, J.L.; Morales, M.; Porro, J.A.; Lanciotti, Agostino; Ristori, V.; Polese, C.; Plaisier, Jasper R.; Lausi, Andrea

doi:10.1016/j.msea.2011.12.010

Cited by 63 publications

(26 citation statements)

References 18 publications

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“…3. In accordance with the above findings, LSP can be applied to the specimens without cracks in a fastener hole, which is in good agreement with previous studies [8][9][10][11]17], and it can be applied for healing the fatigue cracks up to a length of 2.5 ± 0.1 mm detected in a fastener hole with the diameter of 4.8 mm. 4.…”

Section: Discussionsupporting

confidence: 91%

“…They are intended to study the effect of LSP on the specimens with a fastener hole in as-manufactured condition without an initial fatigue crack. According to the study of Ivetic et al [9], it is advantageous when LSP is applied before drilling a hole. Therefore, firstly the specimens were treated by LSP, and subsequently holes were introduced in the specimens.…”

Section: Experimental Programmentioning

confidence: 99%

“…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.…”

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confidence: 99%

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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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Section: Discussionsupporting

confidence: 91%

Section: Experimental Programmentioning

confidence: 99%

mentioning

confidence: 99%

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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 other called laser shock peening without coating (LSPwC) was discover in 1995 [8]. In this process lasers with lower energies (order of a few Joules or less), shorter pulse duration, smaller laser spots, higher coverage and no coating are used [9].…”

Section: Introductionmentioning

confidence: 99%

Laser shock peening without absorbent coating (LSPwC) effect on 3D surface topography and mechanical properties of 6082-T651 Al alloy

Trdan

Porro

Ocaña

et al. 2012

Surface and Coatings Technology

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The influence of nanosecond laser pulses applied by laser shock peening without absorbent coating (LSPwC) with a Q-switched Nd:YAG laser operating at a wavelength of \ = 1064 nm on 6082-T651 Al alloy has been investigated. The first portion of the present study assesses laser shock peening effect at two pulse densities on three-dimensional (3D) surface topography characteristics. In the second part of the study, the peening effect on surface texture orientation and micro-structure modification, i.e. the effect of surface craters due to plasma and shock waves, were investigated in both longitudinal (L) and transverse (T) directions of the laser-beam movement. In the final portion of the study, the changes of mechanical properties were evaluated with a residual stress profile and Vickers micro-hardness through depth variation in the near surface layer, whereas factorial design with a response surface methodology (RSM) was applied. The surface topographic and micro-structural effect of laser shock peening were characterised with optical microscopy, InfiniteFocus® microscopy and scanning electron microscopy (SEM). Residual stress evaluation based on a hole-drilling integral method confirmed higher compression at the near surface layer (33 um) in the transverse direction (Omin) of laser-beam movement, i.e. -407 ±81 MPa and -346 ± 124 MPa, after 900 and 2500 pulses/cm 2 , respectively. Moreover, RSM analysis of micro-hardness through depth distribution confirmed an increase at both pulse densities, whereas LSPwC-generated shock waves showed the impact effect of up to 800 um below the surface. Furthermore, ANOVA results confirmed the insignificant influence of LSPwC treatment direction on micro-hardness distribution indicating essentially homogeneous conditions, in both I and T directions.

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“…If the initiation site is within the compressive stress area, then fatigue lives are improved significantly. For example, in tests on samples with holes, Ivetic et al and Achintha et al found that the laser peen stress field obtained depended on sample thickness and on the relative order of peening and hole drilling operations. The eventual fatigue life obtained depended on whether initiation took place at regions of tensile or compressive residual stress, with only initiation at compressive residual stress fields giving significant improvements.…”

Section: Introductionmentioning

confidence: 99%

Recovery of fatigue life using laser peening on 2024‐T351 aluminium sheet containing scratch damage: The role of residual stress

Smyth

Toparli

Fitzpatrick

et al. 2019

Fatigue Fract Eng Mat Struct

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The aim of the current work was to study the effect of laser shock peening (LSP) when applied to 2‐mm thick 2024‐T351 aluminium samples containing scratch‐like defects in the form of V‐shaped scribes 50 to 150 μm deep. The scribes decreased fatigue life to 5% of that of the pristine material. The effect of laser peening on fatigue life was dependent on the specifics of the peen treatment, ranging from further reductions in life to restoration of the fatigue life to 61% of pristine material. Fatigue life was markedly sensitive to near‐surface tensile residual stress, even if a compressive residual stress field was present at greater depth. Fatigue life after peening was also dependent on sample distortion generated during the peening process. Sample distortion modified local stresses generated by externally applied loads, producing additional life changes. Models based on residual stress intensity and crack closure concepts were successfully applied to predict fatigue life recovery.

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Fatigue in laser shock peened open-hole thin aluminium specimens

Cited by 63 publications

References 18 publications

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

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

Laser shock peening without absorbent coating (LSPwC) effect on 3D surface topography and mechanical properties of 6082-T651 Al alloy

Recovery of fatigue life using laser peening on 2024‐T351 aluminium sheet containing scratch damage: The role of residual stress

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