Left-Side of the Forming Limit Diagram (FLD) under Superimposed Double-Sided Pressure

2012 ◽  
Vol 472-475 ◽  
pp. 653-656
Author(s):  
Jian Guang Liu ◽  
Qing Yuan Meng
Keyword(s):  
Deformation Behavior ◽  
Strain Path ◽  
Damage Model ◽  
Forming Limit Diagram ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
The Finite Element Method ◽  
The Past ◽  
Deformation State

Over the past decades, many kinds of double-sided pressure forming processes have been proposed to improve the formability of lightweight materials which exhibit distinctly poor forming capability. In the present study, the effects of double-sided pressure on the deformation behavior of AA5052-O aluminum alloy sheet metal under tension-compression deformation state are studied numerically using the finite element method based on the Gurson damage model. It is demonstrated that superimposed double-sided pressure significantly increases the left-side of the forming limit diagram and the formability increase value is sensitive to the strain path.

Theoretical and Experimental Evaluation of the Formability of Anisotropic Zinc Sheets

2011 ◽  
Vol 473 ◽  
pp. 390-395 ◽  
Author(s):  
Yann Jansen ◽  
Roland E. Logé ◽  
Marc Milesi ◽  
S. Manov ◽  
Elisabeth Massoni
Keyword(s):  
Metal Forming ◽  
Mechanical Response ◽  
Damage Model ◽  
Rolling Direction ◽  
Forming Limit Diagram ◽  
Tensile Tests ◽  
Forming Limit ◽  
The Past ◽  
Force Criterion ◽  
Critical Strains

. Formability of metal sheet has been widely studied for the past 40 years. This study leads to the well known Forming Limit Diagram (FLD) proposed by Keeler and Backhofen [1]. Such a diagram needs typical drawing and stretching experiments to be achieved. Lots of different metals have been considered as steel, aluminium, titanium or magnesium alloys [2]. Despite of the large amount of papers about sheet metal forming, few deal with Zinc sheets. The material has an anisotropic mechanical response due to its hexagonal crystallographic lattice and its microstructural texture. In the presented work, Nakazima and tensile tests have been performed for different mechanical orientations (0°, 45° and 90° angle to the rolling direction) in order to characterise this typical response. A high anisotropic behaviour has been noticed for the hardening and for the critical strains. The FLD is therefore a function of the orientation. Moreover thickness sensitivity is observed and leads to some criticisms about the plane stress assumption usually used in the FLD predictive models [3, 4]. The Modified Maximum Force Criterion (MMFC) is evaluated, and discussed. Then, this model is compared to a damage model used in [5] within an FEM formulation.

scholarly journals Forming limit curve determination of AA6061-T6 aluminum alloy sheet

2017 ◽  
Vol 20 (K2) ◽  
pp. 51-60
Author(s):  
Hao Huu Nguyen ◽  
Trung Ngoc Nguyen ◽  
Trung Ngoc Nguyen ◽  
Hoa Cong Vu
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Sheet Metal ◽  
Damage Model ◽  
Alloy Sheet ◽  
Analytical Models ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Limit Curve ◽  
Forming Limit Curve

The forming limit curve (FLC) is used in sheet metal forming analysis to determine the critical strain or stress values at which the sheet metal is failing when it is under the plastic deformation process, e.g. deep drawing process. In this paper, the FLC of the AA6061-T6 aluminum alloy sheet is predicted by using a micro-mechanistic constitutive model. The proposed constitutive model is implemented via a vectorized user-defined material subroutine (VUMAT) and integrated with finite element code in ABAQUS/Explicit software. The mechanical behavior of AA6061-T6 sheet is determined by the tensile tests. The material parameters of damage model are identified based on semi-experience method. To archive the various strain states, the numerical simulation is conducted for the Nakajima test and then the inverse parabolic fit technique that based on ISO 124004-2:2008 standrad is used to extracted the limit strain values. The numerical results are compared with the those of MK, Hill and Swift analytical models.

scholarly journals Effect of Die Geometry on the Formability of 5052 Aluminum Alloy in Electromagnetic Impaction Deformation

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1379 ◽  
Author(s):  
Fei Feng ◽  
Jianjun Li ◽  
Rongchuang Chen ◽  
Peng Yuan ◽  
Hongliang Su ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Stress State ◽  
High Speed ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Die Geometry ◽  
The Past ◽  
Pressure Stress ◽  
Insight Into

The formability of aluminum alloy sheet in electromagnetic impaction deformation has attracted the attention of numerous researchers for the past decades. However, the influences of die geometry and high-speed impaction electromagnetic deformation on formability have not been well established, thereby resulting in the formability of the sheet not being developed fully. In this study, the influence of die geometry on the formability of 5052 aluminum alloy in electromagnetic deformation was investigated by comparing the formability of 5052 aluminum alloys formed using a hemispherical die and a cylindrical die. The intriguing finding is that the formability of the 5052 aluminum alloy formed using a cylindrical die is considerably higher than that formed using a hemispherical die. Therefore, die geometry significantly influences the formability of 5052 aluminum alloy. The influence of die geometry on the formability of 5052 aluminum alloy in high-speed impaction electromagnetic deformation was explained in terms of strain rate, pressure stress, and stress state. This investigation enhances insight into the interaction between sheets and dies, and provides a reference for the studying influence of dies on the forming limit of sheets in high-speed impaction deformation.

Numerical Analysis for Process Parameter Effect in Electromagnetic Impact Welding of Aluminum Alloy Sheet

2014 ◽  
Vol 548-549 ◽  
pp. 297-300
Author(s):  
Dae Yong Kim ◽  
Hyeon Il Park ◽  
Ji Hoon Kim ◽  
Sang Woo Kim ◽  
Young Seon Lee
Keyword(s):  
Aluminum Alloy ◽  
Numerical Analysis ◽  
Deformation Behavior ◽  
Three Dimensional ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
Sheet Metals ◽  
Charge Voltage ◽  
Flat Sheet ◽  
Impact Welding

Studies on electromagnetic impact welding between similar or dissimilar flat sheet metals using the flat one turn coil have been recently achieved. In this study, three dimensional electromagnetic-mechanical coupled numerical simulations are performed for the electromagnetic impact welding of aluminum alloy sheets with flat rectangular one turn coil. The deformation behavior during impact welding was examined. The effect of process parameters such as charge voltage, standoff distance and gap distance were investigated.

scholarly journals Forming limit diagram prediction of 6061 aluminum by GTN damage model

2018 ◽  
Vol 19 (2) ◽  
pp. 202 ◽  
Author(s):  
Rasoul Safdarian
Keyword(s):  
Damage Model ◽  
Forming Limit Diagram ◽  
Numerical Results ◽  
Experimental Results ◽  
Correct Selection ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Gtn Model ◽  
Gtn Damage Model

Forming limit diagram (FLD) is one of the formability criteria which is a plot of major strain versus minor strain. In the present study, Gurson-Tvergaard-Needleman (GTN) model is used for FLD prediction of aluminum alloy 6061. Whereas correct selection of GTN parameters’ is effective in the accuracy of this model, anti-inference method and numerical simulation of the uniaxial tensile test is used for identification of GTN parameters. Proper parameters of GTN model is imported to the finite element analysis of Nakazima test for FLD prediction. Whereas FLD is dependent on forming history and strain path, forming limit stress diagram (FLSD) based on the GTN damage model is also used for forming limit prediction in the numerical method. Numerical results for FLD, FLSD and punch’s load-displacement are compared with experimental results. Results show that there is a good agreement between the numerical and experimental results. The main drawback of numerical results for prediction of the right-hand side of FLD which was concluded in other researchers’ studies was solved in the present study by using GTN damage model.

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