Analytical derivation of earing in circular cup drawing based on simple tension properties

Chung, Kwansoo; Kim, Dongun; Park, Taejoon

doi:10.1016/j.euromechsol.2011.01.006

Cited by 25 publications

(12 citation statements)

References 42 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: 93%

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: 93%

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

et al. 2015

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“…In order to evaluate the effect of the initial anisotropy and its evolution in sheet forming simulations, the cylindrical cup drawing test was considered. Since experimental results were not available for the cup drawing test, the earing profiles were instead predicted using an analytical model [34]. To evaluate the capability of the non-associated flow rule to describe anisotropy, anisotropic yield functions under the associated flow rule were additionally considered for the description of the initial anisotropy and the anisotropy after evolution.…”

Section: Prediction Of Earing Profiles In Cup Drawingmentioning

confidence: 99%

“…The analytical model [34] to predict the earing profile assumes that the blank in the flange area undergoes near plane strain deformation. For simplicity, simple compression mode in the circumferential direction is assumed in the flange area.…”

Section: Prediction Of Earing Profiles In Cup Drawingmentioning

confidence: 99%

An Evolutionary Yield Function Model Based on Plastic Work and Non-Associated Flow Rule

Park¹,

Abu-Farha

Pourboghrat³

2019

Metals

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A constitutive law was developed based on the evolutionary yield function to account for the evolution of anisotropy induced by the plastic deformation. For the effective description of anisotropy, the yield stress function and plastic potential were separately defined based on the non-associated flow rule. In particular, for the description of the equivalent status, the accumulated plastic work was employed as an alternative to the accumulated plastic strain. Numerical formulations based on the plastic work were also derived in case the hardening rule, as well as the evolution of the plastic potential and yield stress function, were defined in terms of the plastic work. The developed constitutive law was characterized using the mechanical properties of the multi-phase BAO QP980 steel and niobium sheets at room temperature. From the uniaxial tension tests and the balanced biaxial tension test, separate sets of anisotropic coefficients for each of the plastic potential and yield stress functions were obtained as a function of the plastic work. By comparing with non-evolving yield functions, the importance of the developed constitutive law to properly describe the evolution of the plastic potential and yield function were validated.

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“…The ears generated during the deep drawing of an AA5754-O aluminium cylindrical cup are directly related with the anisotropic behaviour of the sheet (Figure 9). Recent studies indicate that the accurate prediction of the earing profile requires the simultaneous description of both the r-value and yield stress directionalities (Chung et al, 2011;Yoon et al, 2011). The comparison between experimental and numerical earing profile is presented in Figure 22, for the three different temperature conditions.…”

Section: Earing Profilementioning

confidence: 99%

Thermo-mechanical finite element analysis of the AA5086 alloy under warm forming conditions

Neto

Martins

Cunha

et al. 2018

International Journal of Solids and Structures

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Warm forming processes have been successfully applied at laboratory level to overcome some important drawbacks of the Al−Mg alloys, such as poor formability and large springback.However, the numerical simulation of these processes requires the adoption of coupled thermomechanical finite element analysis, using temperature-dependent material models. The numerical description of the thermo-mechanical behaviour can require a large set of experimental tests. These experimental tests should be performed under conditions identical to the ones observed in the forming process. In this study, the warm deep drawing of a cylindrical cup is analysed, including the split-ring test to assess the temperature effect on the springback.Based on the analysis of the forming process conditions, the thermo-mechanical behaviour of the AA5086 aluminium alloy is described by a rate-independent thermo-elasto-plastic material model. The hardening law adopted is temperature-dependent while the yield function is temperature-independent. Nevertheless, the yield criterion parameters are selected based on the temperature of the heated tools. In fact, the model assumes that the temperature of the tools is uniform and constant, adopting a variable interfacial heat transfer coefficient. The accuracy of 2 the proposed finite element model is assessed by comparing numerical and experimental results.The predicted punch force, thickness distribution and earing profile are in very good agreement with the experimental measurements, when the anisotropic behaviour of the blank is accurately described. However, this does not guarantee a correct springback prediction, which is strongly influenced by the elastic properties, namely the Young's modulus.

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Analytical derivation of earing in circular cup drawing based on simple tension properties

Cited by 25 publications

References 42 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

An Evolutionary Yield Function Model Based on Plastic Work and Non-Associated Flow Rule

Thermo-mechanical finite element analysis of the AA5086 alloy under warm forming conditions

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