A new method for acquiring true stress–strain curves over a large range of strains using a tensile test and finite element method

Joun, Man Soo; Eom, Jae-Gun; Lee, Min Cheol

doi:10.1016/j.mechmat.2007.11.006

Cited by 177 publications

(125 citation statements)

References 26 publications

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“…First, we carried out a finite element simulation (Joun et al, 2011) of the test drawing process to investigate the strain distribution (i.e., the initial state) of each specimen. The flow stresses of SCM435 and ESW105 employed in this simulation, and shown in Figure 2, were obtained via the material identification algorithm based on tensile tests (Joun et al, 2007). In the figure, SCM435 exhibited typical strain-hardening behaviour, while ESW105 showed a negligible strain hardening capability.…”

Section: Preparation Of the Specimens And Analysis Of The Drawing Promentioning

confidence: 99%

Quantitative study of the Bauschinger effect in high-strength low-strain-hardening materials for metal forming applications

Joun

Ahn²,

Jin

et al. 2017

IJMPT

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Abstract:In this paper, an experimental study of the Bauschinger effect is carried out in high-strength, low-strain-hardening materials. Pre-heat-treated ESW105 steel, which has a high initial yield stress with negligible strain-hardening capability, is employed in this study. For the sake of comparison, the Bauschinger effect is also investigated in SCM435 steel, which Quantitative study of the Bauschinger effect 21 has typical strain-hardening capability. The Bauschinger effect tends to decrease the forming load during cylinder compression of an ESW105 workpiece initially elongated via a drawing process with proper reduction of area, but does not contribute to forming load reduction in the case of SCM435, even under the same conditions, since it is surpassed by the strain-hardening capability of the material.Keywords: Bauschinger effect; drawn specimen; compression test; high strength; low strain-hardening.Reference to this paper should be made as follows: Joun, M., Ahn, S., Jin, H., Son, Y. and Yoon, D. (2017) 'Quantitative study of the Bauschinger effect in high-strength low-strain-hardening materials for metal forming applications', Int. J. Materials and Product Technology, Vol. 54, Nos. 1/2/3, pp.20-31. Biographical notes:ManSoo Joun is a Professor of Gyeongsang National University (GNU) in South Korea. He is in charge of Technology Innovation Center (TIC) of GNU, which is the only TIC specialised at metal forming and powder forging in South Korea. He is interested in developing intelligent metal forming simulation technologies based on finite element method. He graduated from Seoul National University for his Bachelor degree, from KAIST for his Master degree, and from POSTECH for his PhD degree. His PhD thesis topic was the optimal die shape design in extrusion or drawing. After his PhD course, he has developed and commercialised a metal forming simulator called AFDEX, which is competitive in terms of solution accuracy and user-friendliness.Soontae Ahn is the CEO of Samhwa steel which is a global company producing wires and bars for springs and automotive parts. He is also in charge of the R&D centre of the company. He graduated from Busan National University for his Bachelor degree, from the same university for his Master and PhD degrees. He has developed high tensile spring wires such as energy saver wire (ESW) which has excellent characteristics of impact absorption as well as cold formability.Hotae Jin is a Master's student in Gyeongsang National University of South Korea. He is studying metal forming engineering and the related simulation technology. He is very interested in applying the simulation technology to special incremental metal forming processes including ring rolling process, Mannesmann roll piercing process, roll forging process, etc.Yoheon Son works as Vice President and Director of a research centre at the Youngsin Metal Industrial Company which is one of the leading fastener makers for the automobile, electronic and construction industries. He majored in mechanical engineering at Danko...

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Section: Preparation Of the Specimens And Analysis Of The Drawing Promentioning

confidence: 99%

Quantitative study of the Bauschinger effect in high-strength low-strain-hardening materials for metal forming applications

Joun

Ahn²,

Jin

et al. 2017

IJMPT

Self Cite

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“…These methods [11][12][13] typically involve an iterative optimization of the material model by minimizing the difference between the simulated and experimental load-displacement curves. A disadvantage of these methods…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Determining the stress–strain behaviour at large strains from high strain rate tensile and shear experiments

Peirs

Verleysen

Paepegem

et al. 2011

International Journal of Impact Engineering

116

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“…There are three simulated curves for each experiment, dependent on the type of experiment(s) used to extract the material behaviour. It seems that the material model deduced from solely tensile tests (set3T) or solely shear tests (set3S) is 18003-p. 5 appropriate for the simulation of respectively a tensile or shear experiment but not for both. Different material models are necessary to describe the material behaviour for different loading cases, which is a disadvantage.…”

Section: Extraction Of Constitutive Materials Behaviourmentioning

confidence: 99%

“…More recently developed techniques make use of finite element simulations. These methods [4,5] typically involve an iterative optimization of the material model by minimizing the difference between the simulated and experimental load-displacement curves. An alternative approach to obtain more accurately the local strain in the specimen uses optical (full field) strain measurements such as the moiré phase shifting [6] and digital image correlation technique (DIC).…”

Section: Introductionmentioning

confidence: 99%

Combined experimental and numerical approach for identification of dynamic material model parameters

Peirs

Verleysen

Paepegem

et al. 2010

EPJ Web of Conferences

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Abstract. Extraction of the material stress-strain curve from a dynamic tensile or shear experiment is not straightforward. Indeed, stress and strain are not homogeneously distributed in the specimen, and consequently no one-one relation exists between the measured elongation and strain on one hand, and the measured force and stress on the other hand. This work aims at improving the accuracy of the stress-strain curves calculated from high strain rate experiments and the modelling of the material behaviour. Therefore numerical simulations are used to determine the relationship between the average stress-strain and local effective stress-strain. The material model parameters used in these simulations are improved during an iterative procedure which combines the experimental results and the simulated stress and strain distribution. Stress triaxiality, local temperature and strain rate are taken into account. The method is applied to dynamic tensile and shear experiments on a Ti6Al4V alloy carried out on a split Hopkinson bar set up. The Johnson-Cook model is used to describe the strain rate and temperature dependent material behaviour. The two types of tests are used separately or simultaneously to extract and model the material behaviour. It is found that using tensile and shear experiments simultaneously has clear advantages. The same approach is used to identify parameters for the Johnson-Cook damage initiation criteria.

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A new method for acquiring true stress–strain curves over a large range of strains using a tensile test and finite element method

Cited by 177 publications

References 26 publications

Quantitative study of the Bauschinger effect in high-strength low-strain-hardening materials for metal forming applications

Quantitative study of the Bauschinger effect in high-strength low-strain-hardening materials for metal forming applications

Determining the stress–strain behaviour at large strains from high strain rate tensile and shear experiments

Combined experimental and numerical approach for identification of dynamic material model parameters

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