A viscoplastic model based on a variable strain rate sensitivity index for superplastic sheet metals

Majidi, Omid; Jahazi, Mohammad; Bombardier, Nicolas

doi:10.1007/s12289-018-1443-2

Cited by 14 publications

(17 citation statements)

References 27 publications

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“…However, the power law might not precisely predict the hardening, softening, and damage behavior of superplastic materials. Thus, more advanced visco-plastic constitutive models (e.g., [17,18]) are essential to capture flow and damage behaviors of superplastic metals over a wide range of strain rates. Although some of these models describe the deformation mechanisms of the material during SPF/QPF process, they usually require a tedious experimentation procedure for identifying their parameters.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a new visco-plastic constitutive model based on variable m-value (named hereafter VmV model) has been introduced by the authors [18]. The main elements of the VmV model are expressed as: As discussed by Sorgente et al [12], finite element (FE) simulations have been mainly used in SPF applications for process-optimization purposes.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The VmV model's constants could be determined from three stress-strain curves at different strain rates. Moreover, in this model the effective stress is, explicitly, described by plastic strain and strain rate [18], which facilitates the implementation of the VmV model in FE codes. Thus, this model could be potentially attractive for modelling the SPF/HSBF parts in industrial scales.…”

Section: Introductionmentioning

confidence: 99%

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Finite Element Simulation of High-Speed Blow Forming of an Automotive Component

Majidi

Jahazi

Bombardier³

2018

Metals

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High-speed blow forming (HSBF) is a new technology for producing components with complex geometries made of high strength aluminum alloy sheets. HSBF is considered a hybrid-superplastic forming method, which combines crash forming and gas blow forming. Due to its novelty, optimization of the deformation process parameters is essential. In this study, using the finite element (FE) code ABAQUS, thinning of an aluminum component produced by HSBF under different strain rates was investigated. The impact of element size, variation of friction coefficient, and material constitutive model on thinning predictions were determined and quantified. The performance of the FE simulations was validated through forming of industrial size parts with a complex geometry for the three investigated strain rates. The results indicated that the predictions are sensitive to the element size and the coefficient of friction. Remarkably, compared to a conventional power law model, the variable m-value viscoplastic (VmV) model could precisely predict the thickness variation of the industrial size component.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Finite Element Simulation of High-Speed Blow Forming of an Automotive Component

Majidi

Jahazi

Bombardier³

2018

Metals

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“…Constitutive equations for superplastic metals[22,23] Constitutive equations for superplastic metals[22,23] …”

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confidence: 99%

Numerical Modeling of Superplastic Punchless Deep Drawing Process of a Ti-6Al-4V Titanium Alloy

Skrzat¹,

Wójcik²

2020

Adv. Sci. Technol. Res. J.

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The numerical results of superplastic punchless deep drawing of the Ti-6Al-4V titanium alloy were presented in this paper. The material behavior subjected to the forming process was characterized by deformation-microstructure constitutive equations including the grain growth. Superplastic stress-strain characteristics used in the numerical simulations were computed with the application of authorial program. The explicit integration scheme is used in solving differential equations. The numerical simulations of the super-elastic deep drawing were made with finite element method analysis. The von Mises stress distribution in the blow-forming process was obtained. The possible faults of extrusions caused by the improper load history as well as unsuitable pressure were also presented in this paper. The numerical simulations included in this research allow for the proper choice of material and drawing parameters which can help to optimize the superplastic forming process.

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Prediction of material behavior during biaxial stretching of superplastic 5083 aluminum alloy

Majidi

Jahazi

Bombardier³

2019

Int J Adv Manuf Technol

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In order to predict the flow behavior of a superplastic Al-Mg alloy sheet under near biaxial tension mode, finite element simulation was performed using commercial FE software (ABAQUS). To capture the time-dependent plastic behavior of the material, three constitutive models, i.e., the Voce model, a power law, and a newly introduced variable m value viscoplastic (VmV) model, were implemented in FE simulations. The models' parameters were assessed from the three uniaxial stress-strain curves ranging from 10 −3 to 10 −1 s −1 . To validate the simulation results, Nakazima hemispherical dome testing was performed under isothermal conditions using a constant strain rate of~0.01 s −1 at 450°C. After the tests, the thickness of the deformed parts was measured and the volume fractions of cavities at different locations were assessed using X-ray micro-tomography, and the impact of the strain path on the rate of cavitation was discussed. Based on the obtained results, when the material behavior was modeled using the VmV model, the accuracy of the prediction was about 2 and 5 times better than the ones from power law and Voce model, respectively. It was also observed that the volume fraction of the cavities exponentially increases with equivalent plastic strain and it depends on the strain path history.

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A viscoplastic model based on a variable strain rate sensitivity index for superplastic sheet metals

Cited by 14 publications

References 27 publications

Finite Element Simulation of High-Speed Blow Forming of an Automotive Component

Finite Element Simulation of High-Speed Blow Forming of an Automotive Component

Numerical Modeling of Superplastic Punchless Deep Drawing Process of a Ti-6Al-4V Titanium Alloy

Prediction of material behavior during biaxial stretching of superplastic 5083 aluminum alloy

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