Evaluation of advanced anisotropic models with mixed hardening for general associated and non-associated flow metal plasticity

Taherizadeh, Aboozar; Green, Daniel E.; Yoon, Jeong Whan

doi:10.1016/j.ijplas.2011.05.001

Cited by 59 publications

(21 citation statements)

References 69 publications

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“…Stoughton and Yoon (2009) proposed a non-AFR based anisotropic hardening model that resulted in excellent predictions of hardening curves for rolling, transverse and diagonal directions and for the balanced biaxial stress state. Improvements in prediction of cup height and springback of a U-bend specimen using non-AFR with mixed isotropic-kinematic hardening have been also reported by Taherizadeh et al (2010Taherizadeh et al ( , 2011. Gao et al (2011) showed the significance of the hydrostatic stress on plastic response with the non-associated flow rule.…”

Section: Introductionmentioning

confidence: 69%

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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Section: Introductionmentioning

confidence: 69%

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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“…In this forming process, the plastic anisotropy has important effect on the formation of undulative top edge of the finally drawn cup often termed as earing. Numerous phenomenological orthotropic yield functions with constant (fixed) anisotropy parameters under associated or non-associated flow rule have been tested in this forming process (Yoon et al, 1998(Yoon et al, , 1999(Yoon et al, , 2000Cvitanić et al, 2008;Taherizadeh et al, 2010Taherizadeh et al, , 2011Park and Chung, 2012;Safaei et al, 2013;Vrh et al, 2014;and others). These extensive numerical studies clearly indicate that the predicted earing trend (location of peaks and valleys) is the mirror image of the predicted r-value trend with the respect to the transverse direction, and that the prediction of the earing profile amplitude (the maximum difference in cup heights) is correlated to the prediction of the yield stress anisotropy amplitude.…”

Section: Latin American Journal Of Solids and Structures 14 (2017) 18mentioning

confidence: 99%

Algorithmic Formulations of Evolutionary Anisotropic Plasticity Models Based on Non-Associated Flow Rule

Cvitanić

Kovačić

2017

Lat. Am. j. solids struct.

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“…Various anisotropic yield functions have been proposed to describe the anisotropic deformation behavior of materials. Among them, the quadratic anisotropic yield function (Hill48 yield function) proposed by Hill [5] is the most famous and is widely used because of its simple mathematical expression [6][7][8][9][10][11][12]. However, the Hill48 quadratic yield function can only explain four test results, and the results of the "abnormal" yield behavior observed in some processes involving rolled sheet metals cannot be reasonably described.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Eight Earings in Deep Drawing of 5754O Aluminum Alloy Sheet

Wang

Men

et al. 2019

Chin. J. Mech. Eng.

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Earings appear easily during deep drawing of cylindrical parts owing to the anisotropic properties of materials. However, current methods cannot fully utilize the mechanical properties of material, and the number of earings obtained differ with the simulation methods. In order to predict the eight-earing problem in the cylindrical deep drawing of 5754O aluminum alloy sheet, a new method of combining the yield stress and anisotropy index (r-value) to solve the parameters of the Hill48 yield function is proposed. The general formula for the yield stress and r-value in any direction is presented. Taking a 5754O aluminum alloy sheet as an example in this study, the deformation area in deep drawing is divided into several equal sectorial regions based on the anisotropy. The parameters of the Hill48 yield function are solved based on the yield stress and r-value simultaneously for the corresponding deformation area. Finite element simulations of deep drawing based on new and existing methods are carried out for comparison with experimental results. This study provides a convenient and reliable way to predict the formation of eight earings in the deep drawing process, which is expected to be useful in industrial applications. The results of this study lay the foundation for the optimization of the cylindrical deep drawing process, including the optimization of the blank shape to eliminate earing defects on the final product, which is of great importance in the actual production process.

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Evaluation of advanced anisotropic models with mixed hardening for general associated and non-associated flow metal plasticity

Cited by 59 publications

References 69 publications

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

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

Algorithmic Formulations of Evolutionary Anisotropic Plasticity Models Based on Non-Associated Flow Rule

Prediction of Eight Earings in Deep Drawing of 5754O Aluminum Alloy Sheet

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