Split sleeve cold expansion of AZ31B sheet: Microstructure, texture and residual stress

Faghih, Sasan; Shaha, S.K.; Behravesh, Seyed Behzad; Jahed, Hamid

doi:10.1016/j.matdes.2019.108213

Cited by 43 publications

(21 citation statements)

References 60 publications

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“…The improvement in the compressive residual stress by increasing the expansion percentage can benefit the fatigue life of the structures significantly, which has been investigated in the experimental work done by Gopalakrishna et al. 15 They studied the fatigue life of workpiece made of Al 2024 T3 alloy after SSCE process with the tapered mandrel that is very close to the mandrel design used in our numerical study. They carried out fatigue tests after SSCE process using sinusoidal cyclic loads with a load frequency of 25 Hz and loading stress of 125 MPa.…”

Section: Resultsmentioning

confidence: 93%

“…Over the past decades, experimental and computational approaches have been applied to investigate the residual stresses around the cold expanded hole. Experimentally, x-ray diffraction, neutron diffraction, the strain gage method, Sach's boring, and step drilling 5,11–13,15 have been proposed to quantify the residual stress. However, due to these experimental techniques' limitations such as limited strain sensitivity and resolution, surface condition of the workpiece, x-ray penetration limit, etc., the finite element method (FEM) based computational approach 16,17 has become increasingly popular to investigate residual stress patterns for the hole cold expansion process.…”

Section: Introductionmentioning

confidence: 99%

“…Those factors include the expansion percentage (i.e., the diameter ratio of the expanded hole to the original hole), workpiece material properties, mandrel geometry, and split sleeve geometry, the hole position and size, and the contact condition between components. 5,8,9,15,[18][19][20] It has been shown that there exists an optimum expansion percentage for a given material in the cold hole expansion process because the induced residual stress initially increases to a maximum level and then decreases with the increase in the expansion percentage. 19 The magnitude of residual stresses also increases with increasing workpiece thickness.…”

Section: Introductionmentioning

confidence: 99%

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Finite element parametric study of the split sleeve cold expansion on residual stresses and pulling force

Dey

Kim

Tan

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Split sleeve cold expansion (SSCE) is a crucial cost-effective process to improve the fatigue life of metallic structures with holes in the aerospace industry. In this study, the effects of the workpiece material’s yield strength (290.9 MPa to 377.8 MPa) and the applied SSCE expansion percentage (3.330% to 4.377%) on mandrel pulling force and residual stresses were investigated numerically for aluminum 2024-T351. A three-dimensional finite element (FE) model was developed to simulate the SSCE process using a commercial FE software, ABAQUS. The model geometries, material non-linearities, and contact conditions were adopted according to aerospace industrial applications’ standards. After the numerical model was validated with the published data, a parametric study with variable material properties and expansion percentage was conducted using the FE model. Our parametric study shows that an increase in both the Al workpiece’s yield strength and SSCE expansion percentage can improve the induced residual stresses in the hoop direction around the cold expanded hole; however, the workpiece’s yield strength has a higher impact on the residual stress field. The in-process pulling force during the SSCE process increases with increasing workpiece yield strength and expansion percentage.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Finite element parametric study of the split sleeve cold expansion on residual stresses and pulling force

Dey

Kim

Tan

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…11–18 In addition, CE process also results in several benefits for other alloys such as magnesium alloy, titanium alloy, and steel. 19–21 It is currently believed there are two main reasons of fatigue life enhancements in holed structures treated by CE process: residual stress surrounding hole edges can reduce mean stress near the hole when exposed to cyclic loading, 22–30 and several beneficial microstructure varieties to resistant fatigue such as increasing dislocation density, producing dislocation tangles, and inducing extensive twinning. 11,19…”

Section: Introductionmentioning

confidence: 99%

A novel method to improve fatigue behaviors of holed structures based on electromagnetic force

Zheng

Cao

Zhang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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In this study, a novel method stress wave strengthening (SWS) process based on electromagnetic force was proposed to improve the fatigue life of holed structures. Corresponding tests were carried out to explore the fatigue performance of SWS. Cold expansion (CE) was also investigated for comparison. The fatigue life of SWS and CE samples were evaluated, moreover, the mechanisms of fatigue failures and life enhancements were also discussed. Results showed that double-side SWS extended fatigue life significantly and reduced stiffness degradation more effectively with respect to CE process. Moreover, fatigue cracks commonly appeared at mid-planes of hole surfaces and horizontally grew in SWS samples, which differed a lot from CE samples. Through the residual stress measurement, it is seen that more uniform residual stress along axial direction can be obtained by SWS compared to CE, which can explain the fatigue life enhancement and failure mechanism of SWS method.

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“…To improve the service life and reliability of the devices, it's important to extend the fatigue life of these fastener holes. Conventional hole strengthening methods, named cold working, such as direct cold expansion [2], split sleeve cold expansion [3][4][5][6] and shot peening [7], have already been developed. The principle of these methods is to push the hole wall radially outward, then the elastic/plastic deformation is occurred.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on the effects of circuit parameters on the plastic deformation of fastener holes in thin aluminum alloy via electromagnetic expansion process

Geng

Cao

et al. 2021

Int J Adv Manuf Technol

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The size of plastic deformation zone during fastener hole strengthening is a critical indicator of the strengthening effect. In this study, a considerable plastic deformation zone in 1.5 mm aluminum alloy plate with a hole was produced via electromagnetic strengthening. The finite element analysis results showed that the electromagnetic strengthening process could achieve high compressive hoop residual stress around the fastener hole in thin plate without serious axial deformation compared with conventional cold hole expansion process. The simulation results were experimentally validated by the grid method. Furthermore, for the same discharge energy, the size of plastic deformation zone varies with the discharge capacitance, and there was an optimal combination of the discharge capacitance and discharge voltage.What's more, even the plastic deformation zone was the same at the maxed load, different unloading process during the electromagnetic hole expansion process also had a great influence on the strengthening effect.

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Split sleeve cold expansion of AZ31B sheet: Microstructure, texture and residual stress

Cited by 43 publications

References 60 publications

Finite element parametric study of the split sleeve cold expansion on residual stresses and pulling force

Finite element parametric study of the split sleeve cold expansion on residual stresses and pulling force

A novel method to improve fatigue behaviors of holed structures based on electromagnetic force

Numerical investigation on the effects of circuit parameters on the plastic deformation of fastener holes in thin aluminum alloy via electromagnetic expansion process

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