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 Aluminum Alloy Sheet-Forming Limit Curve Prediction Based on Original Measured Stress–Strain Data and Its Application in Stretch-Forming Process

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1129 ◽  
Author(s):  
Lirong Sun ◽  
Zhongyi Cai ◽  
Dongye He ◽  
Li Li
Keyword(s):  
Aluminum Alloy ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Limit Curve ◽  
Forming Process ◽  
Forming Limit Curve ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation

A new method, by directly utilizing original measured data (OMD) of the stress–strain relation in the Marciniak–Kuczynski (M–K) model, was proposed to predict the forming limit curve (FLC) of an aluminum alloy sheet. In the groove zone of the M–K model, by establishing the relations of the equivalent strain increment, the ratio of shear stress to the first principle stress and the ratio of the second principle stress to the first principle stress, the iterative formula was established and solved. The equations of theoretical forming limits were derived in detail by using the OMD of the stress–strain relation. The stretching specimens of aluminum alloy 6016-T4 were tested and the true stress–strain curve of the material was obtained. Based on the numerical simulations of punch-stretch tests, the optimized specimens’ shape and test scheme were determined, and the tests for FLC were carried out. The FLC predicted by the proposed method was more consistent with the experimental results of FLC by comparing the theoretical FLCs based on OMD of the stress–strain relation and of that based on traditional power function. In addition, the influences of anisotropic parameter and groove angle on FLCs were analyzed. Finally, the FLC calculated by the proposed method was applied to analyze sheet formability in the stretch-forming process, and the predicted results of FLC were verified by numerical simulations and experiments. The fracture tendency of the formed parts can be visualized in the forming limit diagram (FLD), which has certain guiding significance for fracture judgment in the sheet-forming process.

A Constitutive Model of 6111-T4 Aluminum Alloy Sheet Based on the Warm Tensile Test

2013 ◽  
Vol 23 (3) ◽  
pp. 1107-1113 ◽  
Author(s):  
Lin Hua ◽  
Fanzhi Meng ◽  
Yanli Song ◽  
Jianing Liu ◽  
Xunpeng Qin ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Tensile Test ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet

Experimental and Numerical Analysis of Forming Limits in CNC Incremental Sheet Forming

2007 ◽  
Vol 344 ◽  
pp. 511-518 ◽  
Author(s):  
Markus Bambach ◽  
M. Todorova ◽  
Gerhard Hirt
Keyword(s):  
Sheet Metal ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Negative Slope ◽  
Evaluation Procedure ◽  
Forming Limit ◽  
Limit Curve ◽  
Forming Limit Curve ◽  
Forming Limits ◽  
Straight Line

Asymmetric incremental sheet forming (AISF) is a relatively new manufacturing process for the production of low volumes of sheet metal parts. Forming is accomplished by the CNC controlled movements of a simple ball-headed tool that follows a 3D trajectory to gradually shape the sheet metal blank. Due to the local plastic deformation under the tool, there is almost no draw-in from the flange region to avoid thinning in the forming zone. As a consequence, sheet thinning limits the amount of bearable deformation, and thus the range of possible applications. Much attention has been given to the maximum strains that can be attained in AISF. Several authors have found that the forming limits are considerably higher than those obtained using a Nakazima test and that the forming limit curve is approximately a straight line (mostly having a slope of -1) in the stretching region of the FLD. Based on these findings they conclude that the “conventional” forming limit curves cannot be used for AISF and propose dedicated tests to record forming limit diagrams for AISF. Up to now, there is no standardised test and no evaluation procedure for the determination of FLCs for AISF. In the present paper, we start with an analysis of the range of strain states and strain paths that are covered by the various tests that can be found in the literature. This is accomplished by means of on-line deformation measurements using a stereovision system. From these measurements, necking and fracture limits are derived. It is found that the fracture limits can be described consistently by a straight line with negative slope. The necking limits seem to be highly dependent on the test shapes and forming parameters. It is concluded that standardisation in both testing conditions and the evaluation procedures is necessary, and that a forming limit curve does not seem to be an appropriate tool to predict the feasibility of a given part design.

scholarly journals Forming Limit Research of 5182 Aluminum Alloy Sheet Based on Lou-2013 Ductile Fracture Criterion

2019 ◽  
Vol 55 (16) ◽  
pp. 47 ◽  
Author(s):  
YANG Zhuoyun ◽  
ZHAO Changcai ◽  
DONG Guojiang ◽  
CHEN Guang ◽  
ZHU Liangjin ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Ductile Fracture ◽  
Fracture Criterion ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Ductile Fracture Criterion

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.

scholarly journals Process metallurgy design for high-formability aluminum alloy sheet metal generation by using two-scale FEM

2011 ◽  
Vol 10 ◽  
pp. 2250-2255 ◽  
Author(s):  
Hiroyuki Kuramae ◽  
Hidetoshi Sakamoto ◽  
Hideo Morimoto ◽  
Eiji Nakamachi
Keyword(s):  
Aluminum Alloy ◽  
Sheet Metal ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
Process Metallurgy
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