Experiment and modeling based studies of the mesoscaled deformation and forming limit of Cu/Ni clad foils using a newly developed damage model

2021 ◽  
pp. 103173
Author(s):  
Chuanjie Wang ◽  
Haiyang Wang ◽  
Gang Chen ◽  
Qiang Zhu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Damage Model ◽  
Forming Limit

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.

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.

Application of Barlat Yld-96 Yield Criterion for Predicting Formability of Pre-Strained Dual Phase Steel Sheets

2016 ◽  
Author(s):  
Shamik Basak ◽  
Sushanta Kumar Panda
Keyword(s):  
Dual Phase Steel ◽  
Yield Criterion ◽  
Thin Sheet ◽  
Damage Model ◽  
Forming Limit Diagram ◽  
Plasticity Theory ◽  
Forming Limit ◽  
Dual Phase ◽  
Strain Paths ◽  
Anisotropy Coefficients

The selection of advanced material model considering the anisotropy mechanical properties of the thin sheet is vital in order to estimate stress based forming limit diagram (σ-FLD). In present study associative plasticity theory was applied indulging Barlat Yld-96 anisotropy yield function and the Swift hardening law was implemented for estimating the limiting stresses from the conventional strain FLD (ε-FLD) of an automotive grade dual phase steel DP600. Three different approaches were made to evaluate Yld-96 anisotropy coefficients using experimental results of stack compression and tensile tests. To impose complex strain path, two stage stretch forming processes were simulated in finite element solver LS-DYNA. After biaxial pre-straining, the sample geometries were varied to achieve different strain paths during the second stage of deformation. The results indicated that there was negligible difference in limiting stress estimated by Yld-96 plasticity theory when the anisotropy coefficients were calculated based on plastic strain at ultimate tensile strength compare to that by minimum plastic work method. It was concluded that the dynamic shift of ε-FLD could be restricted by σ-FLD estimated using Yld 96 plasticity theory, and hence it was proposed to be a suitable damage model to evaluate formability of pre-strained DP600 steels.

Prediction of Forming Limit of Dual-Phase 500 Steel Sheets Using the GTN Ductile Damage Model in an Innovative Hydraulic Bulging Test

JOM ◽  
2018 ◽  
Vol 70 (8) ◽  
pp. 1542-1547 ◽  
Author(s):  
Xiao-Lei Cui ◽  
W. W. Zhang ◽  
Zhi-Chao Zhang ◽  
Yi-Zhe Chen ◽  
Peng Lin ◽  
...  
Keyword(s):  
Damage Model ◽  
Ductile Damage ◽  
Forming Limit ◽  
Dual Phase ◽  
Steel Sheets ◽  
Bulging Test ◽  
Hydraulic Bulging

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.

A Unified Damage Approach for Predicting Forming Limit Diagrams

1997 ◽  
Vol 119 (4) ◽  
pp. 346-353 ◽  
Author(s):  
C. L. Chow ◽  
L. G. Yu ◽  
M. Y. Demeri
Keyword(s):  
Plastic Deformation ◽  
Sheet Metal ◽  
Damage Model ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Unified Approach ◽  
Nonuniform Deformation ◽  
Localized Necking ◽  
Micro Cracks ◽  
Three Phases

Plastic deformation in sheet metal consists of four distinct phases, namely, uniform deformation, diffuse necking, localized necking, and final rupture. The last three phases are commonly known as nonuniform deformation. A proper forming limit diagram (FLD) should include all three phases of the nonuniform deformation. This paper presents the development of a unified approach to the prediction of FLD to include all three phases of nonuniform deformation. The conventional method for predicting FLD is based on localized necking and adopts two fundamentally different approaches. Under biaxial loading, the Hill’s plasticity method is often chosen when α(=ε2/ε1) <0. On the other hand, the M-K method is typically used for the prediction of localized necking when α > 0 or when the biaxial stretching of sheet metal is significant. The M-K method, however, suffers from the arbitrary selection of the imperfection size, thus resulting in inconsistent predictions. The unified approach takes into account the effects of micro-cracks/voids on the FLD. All real-life materials contain varying sizes and degrees of micro-cracks/voids which can be characterized by the theory of damage mechanics. The theory is extended to include orthotropic damage, which is often observed in extensive plastic deformation during sheet metal forming. The orthotropic FLD model is based on an anisotropic damage model proposed recently by Chow and Wang (1993). Coupling the incremental theory of plasticity with damage, the new model can be used to predict not only the forming limit diagram but also the fracture limit diagram under proportional or nonproportional loading. In view of the two distinct physical phenomena governing the cases when α(=ε2/ε1) < or α > 0, a set of instability criteria is proposed to characterize all three phases of nonuniform deformation. The orthotropic damage model has been employed to predict the FLD of VDIF steel (Chow et al, 1996) and excellent agreement between the predicted and measured results has been achieved as shown in Fig. 1. The damage model is extended in this paper to examine its applicability and validity for another important engineering material, namely aluminum alloy 6111-T4.

Evaluation of Bendability of Hot-Rolled S960 Grade Steel Using Optical Strain Measurements and FE-Modelling

2015 ◽  
Vol 651-653 ◽  
pp. 610-616 ◽  
Author(s):  
Anna Maija Arola ◽  
Antti J. Kaijalainen ◽  
Vili Kesti
Keyword(s):  
Damage Model ◽  
Forming Limit ◽  
Forming Process ◽  
Fe Modelling ◽  
Bending Tests ◽  
Strain Measurements ◽  
Air Bending ◽  
Bending Process ◽  
Optical Strain ◽  
Hot Rolled

Bending is an important forming process for ultra-high strength steel (UHSS) because it is cost-effective, fast and in many cases it can be used to replace welding in a part manufacturing processes. One major challenge in air bending of UHSS is to predict the limits for bendability since the traditional methods for failure prediction, such as forming limit diagram (FLD), cannot generally be applied to bending process. In this paper, 3D FE-modelling coupled with a CDM-damage model is used to simulate the air bending process and to determine the bendability limits for a hot-rolled 960MPa grade. Damage parameters for the CDM-model are determined by using optical strain measurements and inverse modelling of the tensile test. Three point bending tests with optical strain measuring were carried out to determine the deformation field of the outer bend in different bending angles and the results of the bending simulation are compared with the strain measurements of the bending tests. The damage model is then calibrated using the experimental results of the bending tests to adjust the crack occurrence in the simulation. A good agreement was found between simulations and experimental measurements.

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