A new analytical theory for earing generated from anisotropic plasticity

Yoon, Jeong Whan; Dick, Robert E.; Barlat, Frédéric

doi:10.1016/j.ijplas.2011.01.002

Cited by 80 publications

(34 citation statements)

References 32 publications

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“…Since during deep drawing of cylindrical cups the sheet located between the blank-holder and die is subjected to uniaxial compression [41], the anisotropic behaviour of the aluminium alloy leads to a non-uniform thickening of the flange along the circumferential direction. The sheet thickening is higher near the transverse direction than in the rolling direction [42,43] because the Lankford coefficient is smaller than 1.0 in the rolling direction and higher than 1.0 in the transverse direction (see Fig. 4 (b)).…”

Section: Wrinkle Patternmentioning

confidence: 99%

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

et al. 2015

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The recent trend to reduce the thickness of metallic sheets used in forming processes strongly increases the likelihood of the occurrence of wrinkling. Thus, in order to obtain defect-free components, the prediction of this kind of defect becomes extremely important in the tool design and selection of process parameters. In this study, the sheet metal forming process proposed as a benchmark in the Numisheet 2014 conference is selected to analyse the influence of the tool geometry on wrinkling behaviour, as well as the reliability of the developed numerical model. The side-wall wrinkling during the deep drawing process of a cylindrical cup in AA5042 aluminium alloy is investigated through finite element simulation and experimental measurements. The material plastic anisotropy is modelled with an advanced yield criterion beyond the isotropic (von Mises) material behaviour. The results show that the shape of the wrinkles predicted by the numerical model is strongly affected by the finite element mesh used in the blank discretization. The accurate modelling of the plastic anisotropy of the aluminium alloy yields numerical results that are in good agreement with the experiments, particularly the shape and location of the wrinkles. The predicted punch force evolution is strongly influenced by the friction coefficient used in the model. Moreover, the two punch geometries provide drawn cups with different wrinkle waves, mainly differing in amplitude.

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Section: Wrinkle Patternmentioning

confidence: 99%

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

et al. 2015

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“…Therefore, the material behavior will be dictated by the stress and r -values predicted for this stress state, which for the YLD91 are the same as for a tensile stress state. [17]). Figure 8 presents the evolution of the ratio between the plastic strain along the radial and the thickness direction, estimated from the numerical results, and the r -values estimated, for both yield criteria.…”

Section: Resultsmentioning

confidence: 99%

“…These results are in accordance with the fact that the compression yield stresses in the rolling direction will have a direct impact on the material behavior at the transverse direction, as shown in Figure 7. In fact, the behavior of the rim in the direction defined by θ (with the rolling direction) is controlled by the material compression properties in the direction defined by 90 θ − [17] [18]. The fact that the CPB06 compression yield stress at 90º is over predicted, has as consequence the pronounced decrease in height of the earing profile, mainly between 0º and 60º.…”

Section: Resultsmentioning

confidence: 99%

Tension-compression asymmetry modelling: strategies for anisotropy parameters identification.

et al. 2016

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Abstract. This work presents details concerning the strategies and algorithms adopted in the fully implicit FE solver DD3IMP to model the orthotropic behavior of metallic sheets and the procedure for anisotropy parameters identification. The work is focused on the yield criterion developed by Cazacu, Plunkett and Barlat, 2006 [1], which accounts for both tension-compression asymmetry and orthotropic plastic behavior. The anisotropy parameters for a 2090-T3 aluminum alloy are identified accounting, or not, for the tension-compression asymmetry. The numerical simulation of a cup drawing is performed for this material, highlighting the importance of considering tension-compression asymmetry in the prediction of the earing profile, for materials with cubic structure, even if this phenomenon is relatively small.

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“…The blank was meshed using approximately 700 first order reduced integration quadrilateral shell elements with 11 Gauss integration points through the thickness. Earing profiles of AA 2090-T3 predicted from Barlat et al's (2005) (Yld2004-18p) and an analytical approach can be found in the works of Yoon et al (2006Yoon et al ( , 2011, respectively. Earing simulation to predict more than four ears using Yld20000-2d under non-associated flow can be found at Yoon et al (2007), Park and Chung (2012) and Safaei et al (2013b).…”

Section: Impact Of Model Simplification On Cup Drawing Simulationmentioning

confidence: 99%

Study on the definition of equivalent plastic strain under non-associated flow rule for finite element formulation

Safaei

Yoon

Waele

2014

International Journal of Plasticity

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a b s t r a c tAs opposed to associated flow rule (AFR) in which yield function and plastic potential are equal, the different definitions for them is an inherent characteristic of non-associated flow rule (non-AFR). This imposes a specific relation (but not equality) between equivalent plastic strain and plastic compliance factor. Unavoidably, this leads to a laborious effort for FE implementation of non-associated constitutive model specifically when several internal variables (such as kinematic hardening or damage parameters) are involved. This paper is mainly devoted to studying the conditions at which the non-AFR approach can be simplified so that the numerical implementation scheme is more convenient without loss of accuracy. It will be shown that by scaling the plastic potential function, the equality of equivalent plastic strain and compliance factor can be reserved. The effect of scaling of the non-AFR based on Barlat et al.'s (2003) anisotropic model (called Yld2000-2d) is comprehensively studied with FE simulation of tensile loading under uniaxial tensions along the different orientations as well as balanced biaxial stress condition. A fully implicit return-mapping scheme was introduced for stress integration of the constitutive model in a User-defined MATerial subroutine (UMAT). Cup drawing simulations of a highly textured aluminum alloy 2090-T3 were performed using simplified and original approaches. The results prove that the proposed simplified technique is a reliable alternative for the full expression.

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A new analytical theory for earing generated from anisotropic plasticity

Cited by 80 publications

References 32 publications

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

Tension-compression asymmetry modelling: strategies for anisotropy parameters identification.

Study on the definition of equivalent plastic strain under non-associated flow rule for finite element formulation

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