Effect of elastic prestress on the laser peen forming of aluminum alloy 2024-T351: Experiments and eigenstrain-based modeling

Hu, Yongxiang; Li, Zhi; Yu, Xiongchao; Yao, Zhenqiang

doi:10.1016/j.jmatprotec.2015.02.030

Cited by 45 publications

(8 citation statements)

References 12 publications

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“…Whereas eigenstrains along the transverse direction are almost superimposed, the magnitude of eigenstrains along the prestress direction increases with prestress curvature. Similar results were reported by Hu et al (2015) for laser peening simulation of 2024-T3 aluminum sheets. Similarly, sheets 2:1-T and 1:1-L, which deformed into cylindrical shapes, display larger eigenstrains along the bending (L) direction whereas other unconstrained sheets, which deformed into elliptical or nearly spherical shapes, display similar eigenstrains in both directions (see Figure 8).…”

Section: Influence Of Prestresssupporting

confidence: 89%

Peen forming and stress peen forming of 2024-T3 aluminum sheets. Part 2: eigenstrain analysis

Miao¹,

Lévesque²,

Gosselin³

2021

Preprint

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In this study we use the theory of eigenstrains to investigate how different sources of anisotropy affected the results of shot peen forming experiments reported in Part~1. The specimens consisted of 4.9 mm thick 2024-T3 aluminum sheets uniformly shot peened on one face that were either free to deform or held onto a prestressing jig during peening. Potential sources of anisotropy included the plastic anisotropy of rolled aluminum, anisotropic initial stresses that redistribute when their equilibrium is disturbed by peenning, the geometry of the specimens, and externally applied prestress. For the alloy and peening conditions considered, plastic anisotropy had no discernable influence on the resulting shape of the peen formed specimens. Initial residual stresses, on the other hand, caused slightly larger bending loads in the rolling direction of the alloy. Although the magnitude of these loads was approximately 30 times smaller than peening-induced loads, it was sufficient to overcome the geometric preference for rectangular sheets to bend along their long side and cause all unconstrained specimens to bend along the rolling direction instead. Once the sheets started to deform, larger plastic strains developed in the bending direction. We show that this effect is equivalent to that used in the variant of the process called stress peen forming where parts are elastically prestressed during peening to obtain larger plastic strains in directions in which the material is stretched.

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Section: Influence Of Prestresssupporting

confidence: 89%

Peen forming and stress peen forming of 2024-T3 aluminum sheets. Part 2: eigenstrain analysis

Miao¹,

Lévesque²,

Gosselin³

2021

Preprint

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show abstract

“…xx (Hu et al, 2015). As a consequence, it was necessary to reconstruct both in-plane components of the eigenstrain field, as both enter the computation of residual stresses (simulated residual stress profiles that the reconstruction procedure attempted to match with measurements depend on the whole eigenstrain field).…”

Section: Applications and Resultsmentioning

confidence: 99%

“…If the latter is known, or if it can be estimated with sufficient accuracy, then the computation of stresses and distortions -the direct problem -can be dealt with as an inclusion problem (Mura, 1987). This approach has been successfully applied to a variety of engineering problems as illustrated by Deng et al (2007), Hu et al (2015), and Depouhon et al (2015) where the authors respectively investigated residual stresses and distortions induced by welding, laser peening and thermo-mechanical treatments. In all of these studies, the authors made use of a two-step procedure involving a local analysis to compute eigenstrains followed by a global springback analysis to obtain the final deformed shape.…”

Section: Eigenstrainsmentioning

confidence: 99%

Simulating shot peen forming with eigenstrains

Faucheux

Gosselin

Lévesque

2018

Journal of Materials Processing Technology

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Shot peen forming is a cold work process used to shape thin metallic components by bombarding them with small shots at high velocities. Several simulation procedures have been reported in the literature for this process, but their predictive capabilities remain limited as they systematically require some form of calibration or empirical adjustments. We intend to show how procedures based on the concept of eigenstrains, which were initially developed for applications in other fields of residual stress engineering, can be adapted to peen forming and stress-peen forming. These tools prove to be able to reproduce experimental results when the plastic strain field that develop inside a part is known with sufficient accuracy. They are, however, not mature enough to address the forming of panels that are free to deform during peening. For validation purposes, we peen formed several 1 by 1 meter 2024-T3 aluminum alloy panels. These experiments revealed a transition from spherical to cylindrical shapes as the panel thickness is decreased for a given treatment, that we show results from an elastic instability.

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“…Hu et al [2] investigated the dependency of bending on the laser power intensity and specimen thickness. Further work of Hu et al [3] identified elastic prestress as a mean to further increase bending by LPF. The feasibility of LPF for composites such as fiber metal laminates has been demonstrated [4].…”

Section: Introductionmentioning

confidence: 97%

Numerical Investigation of Influence of Spot Geometry in Laser Peen Forming of Thin-Walled Ti-6Al-4V Specimens

Pöltl

Keller

Chupakhin

et al. 2022

KEM

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The aviation industry demands thin-walled structures of high dimensional accuracy. Varying radii and individual use-cases, e.g. for repair purpose, require flexible forming techniques. Laser peen forming (LPF) represents such a forming process providing precise energy input by a pulsed laser over a wide energy range. Among adjustable parameters such as laser intensity and focus size, the spot shape, i.e. square and circular, is usually fixed for a specific laser system. As the spot shape is a crucial parameter, this work focuses on the effect of the spot shape on structural deformation after LPF application. Therefore, models for laser peen forming of thin-walled Ti-6Al-4V strips for LPF systems with circular and square focus shapes are set up. Geometric conditions on both focus shapes ensure equal energy input during the laser processing. The numerical simulation relies on the so called eigenstrain method, leading to a cost-efficient calculation of resulting deformation after the dynamic LPF process. Square-based peening pattern exhibit higher deflection. For increasing spot size, the deflection difference between square and circle-based patterns increase slightly.

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Effect of elastic prestress on the laser peen forming of aluminum alloy 2024-T351: Experiments and eigenstrain-based modeling

Cited by 45 publications

References 12 publications

Peen forming and stress peen forming of 2024-T3 aluminum sheets. Part 2: eigenstrain analysis

Peen forming and stress peen forming of 2024-T3 aluminum sheets. Part 2: eigenstrain analysis

Simulating shot peen forming with eigenstrains

Numerical Investigation of Influence of Spot Geometry in Laser Peen Forming of Thin-Walled Ti-6Al-4V Specimens

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