Numerical simulation and experimental investigation of ductile fracture in SPIF using modified GTN model

Gatea, Shakir; Lü, Bin; Ou, Hengan; McCartney, D.G.

doi:10.1051/matecconf/20152104013

Cited by 8 publications

(2 citation statements)

References 15 publications

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“…The ductile damage in ISF of pure Ti sheet was investigated numerically using shear modified GTN damage model. There was a good correlation of the fracture depth when the shear modified GTN model results were compared with the experimental ISF test [23].…”

Section: Introductionmentioning

confidence: 83%

Evaluation of formability and fracture of pure titanium in incremental sheet forming

Gatea

et al. 2017

Int J Adv Manuf Technol

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A forming limit diagram (FLD) is commonly used as a useful means for characterising the formability of sheet metal forming processes. In this study, the Nakajima test was used to construct the forming limit curve at necking (FLCN) and fracture (FLCF). The results of the FLCF are compared with incremental sheet forming (ISF) to evaluate the ability of the Nakajima test to describe the fracture in ISF. Tests were carried out to construct the forming limit diagram at necking and fracture to cover the strain states from uniaxial tension to equi-biaxial tension with different stress triaxialities-from 0.33 for uniaxial tension to 0.67 for equi-biaxial tension. Due to the fact that the Gurson-Tvergaard-Needleman (GTN) model can be used to capture fracture occurrence at high stress triaxiality, and the shear modified GTN model (Nahshon-Hutchinson's shear mechanism) was developed to predict the fracture at zero stress or even negative stress triaxiality, the original GTN model and shear modified GTN model may be not suitable to predict the fracture in all samples of the Nakajima test as some samples are deformed under moderate stress triaxiality. In this study, the fractures are compared using the original GTN model, shear modified GTN model and the Nielsen-Tvergaard model with regard to stress triaxiality. To validate the ability of these models, and to assess which model is more accurate in predicting the fracture with different stress triaxialities, finite element (FE) simulations of the Nakajima test were compared with an experimental results to evaluate the applicability of the Nakajima test to characterise the fracture from ISF. The experimental and FE results showed that the shear modified GTN model could predict the fracture accurately with samples under uniaxial tension condition due to low stress triaxiality and that the original GTN model is suitable for an equi-biaxial strain state (high stress triaxiality), whereas the stress triaxiality modified GTN model should be considered for samples which have moderate stress triaxiality (from plain strain to biaxial strain). The numerical and experimental FLCF of pure titanium from the Nakajima test showed a good agreement between the experimental and numerical results of ISF.

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Section: Introductionmentioning

confidence: 83%

Evaluation of formability and fracture of pure titanium in incremental sheet forming

Gatea

et al. 2017

Int J Adv Manuf Technol

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“…In more recent work, Gatea et al [71] developed a modified Gurson-Tvergaard-Needleman (GTN) model that can be used to predict ductile fracture in SPIF. In this study, parameters for the model were determined using tensile tests, which included the void volume fraction.…”

Section: Forming Mechanics and Formabilitymentioning

confidence: 99%

Single point incremental forming: An assessment of the progress and technology trends from 2005 to 2015

Behera

Sousa

Ingarao

et al. 2017

Journal of Manufacturing Processes

225

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The last decade has seen considerable interest in flexible forming processes. Among the upcoming flexible forming techniques, one that has captured a lot of interest is Single Point Incremental Forming (SPIF), where a flat sheet is incrementally deformed into a desired shape by the action of a tool that follows a defined toolpath conforming to the final part geometry. Research on SPIF in the last ten years has focused on defining the limits of this process, understanding the deformation mechanics and material behavior and extending the process limits using various strategies. This paper captures the developments that have taken place over the last decade in academia and industry to highlight the current state of the art in this field. The use of different hardware platforms, forming mechanics, failure mechanism, estimation of forces, use of toolpath and tooling strategies, development of process planning tools, simulation of the process, aspects of sustainable manufacture and current and future applications are individually tracked to outline the current state of this process and provide a roadmap for future work on this process.

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Ductile fracture prediction and forming assessment of AA6061-T6 aluminum alloy sheets

Nguyen

2017

Int J Fract

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Numerical simulation and experimental investigation of ductile fracture in SPIF using modified GTN model

Cited by 8 publications

References 15 publications

Evaluation of formability and fracture of pure titanium in incremental sheet forming

Evaluation of formability and fracture of pure titanium in incremental sheet forming

Single point incremental forming: An assessment of the progress and technology trends from 2005 to 2015

Ductile fracture prediction and forming assessment of AA6061-T6 aluminum alloy sheets

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