scholarly journals Application of a GTN Damage Model Predicting the Fracture of 5052-O Aluminum Alloy High-Speed Electromagnetic Impaction

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 761 ◽  
Author(s):  
Fei Feng ◽  
Jianjun Li ◽  
Peng Yuan ◽  
Qixian Zhang ◽  
Pan Huang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Fracture Behavior ◽  
Volume Fraction ◽  
Damage Model ◽  
Weight Ratio ◽  
Model Parameters ◽  
Highly Nonlinear ◽  
Gtn Damage Model ◽  
Increasing Demand

An increasing demand exists within the automotive industry to utilize aluminum alloy sheets because of their excellent strength-weight ratio and low emissions, which can improve fuel economy and reduce environmental pollution. High-speed automobile impactions are complicated and highly nonlinear deformation processes. Thus, in this paper, a Gurson-Tvergaard-Needleman (GTN) damage model is used to describe the damage behavior of high-speed electromagnetic impaction to predict the fracture behavior of 5052-O aluminum alloy under high-speed impaction. The parameters of the GTN damage model are obtained based on high-speed electromagnetic forming experiments via scanning electron microscopy. The high-speed electromagnetic impaction behavior process is analyzed according to the obtained GTN model parameters. The shape of the high-speed electromagnetic impaction in the numerical simulations agrees with the experimental results. The analysis of the plastic strain and void volume fraction distributions are analyzed during the process of high-speed impact, which indicates the validity of using the GTN damage model to describe or predict the fracture behavior of high-speed electromagnetic impaction.

scholarly journals Evaluating the Applicability of GTN Damage Model in Forward Tube Spinning of Aluminum Alloy

Metals ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 136 ◽  
Author(s):  
Xianxian Wang ◽  
Mei Zhan ◽  
Jing Guo ◽  
Bin Zhao
Keyword(s):  
Aluminum Alloy ◽  
Damage Model ◽  
Tube Spinning ◽  
Gtn Damage Model

Press-Formability of Aluminum Alloy Sheets of Solution-Hardening Type

1983 ◽  
Vol 105 (4) ◽  
pp. 235-242 ◽  
Author(s):  
N. Kawai ◽  
T. Mori ◽  
T. Nozaki
Keyword(s):  
Aluminum Alloy ◽  
Fracture Behavior ◽  
Plastic Anisotropy ◽  
Weight Ratio ◽  
High Strength ◽  
Solution Hardening ◽  
Solution Type ◽  
Metal Sheets ◽  
The Press ◽  
Press Formability

Recently, formable metal sheets with a high strength-to-weight ratio have been developed especially to conserve energy and resources. For this purpose, two conditions are necessary: the strengthening of the sheet metal and improvement of the press-formability, which are difficult to obtain together. In the present study, the conditions necessary for this are examined using solid-solution type aluminum alloy sheets. Moreover, a new measure to assess press-formability is proposed in terms of the strain-hardening capability and plastic-anisotropy based on fracture behavior of sheet metals.

Study on Fracture Behavior of Steel Strip under Cold Rolling Forming Process Based on GTN Damage Model

2013 ◽  
Vol 779-780 ◽  
pp. 126-129
Author(s):  
Jian Jun Chen ◽  
Yu Xi Yan ◽  
Quan Sun ◽  
Hong Liang Pan
Keyword(s):  
Crack Propagation ◽  
Fracture Behavior ◽  
Steel Strip ◽  
Damage Model ◽  
Forming Process ◽  
Strip Steel ◽  
Initiation And Propagation ◽  
Gtn Damage Model ◽  
Edge Cracks ◽  
Simulation Results

In this paper the behavior of crack propagation of the strip steel is investigated by using the Gurson-Tvergaard-Needleman (GTN) damage model. The damage parameters used in the damage model are determined by tension experiments and SEM observation. With the aid of finite element method the influences of rolling ruduction and tension on crack propagation are systematically analyzed. The numerical results show that the GTN damage model is available to prediction the initiation and propagation of edge cracks during rolling forming process and the simulation results agrees well with the experimental results.

FEA Simulation of Clinching Process Based on GTN Damage Model

2013 ◽  
Vol 652-654 ◽  
pp. 2254-2260 ◽  
Author(s):  
Bai Jun Shi ◽  
Shu Hui Liao ◽  
Song Peng ◽  
Hang Li
Keyword(s):  
Simulation Model ◽  
Sheet Material ◽  
Damage Model ◽  
Model Parameters ◽  
Material Damage ◽  
Gtn Damage Model ◽  
Fea Simulation ◽  
Simulation Results ◽  
Clinch Joining ◽  
Joining Process

In this work, the Gurson-Tvergaard-Needleman (GTN) damage model is adopted to depict the material damage during the clinch joining process in a simulation-based theoretical model. The parameters of the GTN model which influence the void nucleation, growth and coalescence are identified. Their values of a specific material, C45E4 (ISO) steel, have been determined after carefully comparing the simulation results with the real sheet material tensile test. The established GTN damage model parameters are then imported into the simulation model to investigate the material damage during the mechanical clinch joining process. The Finite Element Analysis (FEA) simulation results show promising, because the material’s initial damage position can be located and analyzed. For a given design, the initial fracture point was predicted which is located on the inner side of the clinched joint neck of the upper sheet, which matches with the results of the experimental test very well. It can be concluded that the incorporation of GTN damage model has extend the capability of the simulation model.

Experimental Design and Data Collection for Dynamic Fragmentation Experiments

2010 ◽  
Author(s):  
Joseph Weiderhold ◽  
David E. Lambert ◽  
Michael Hopson
Keyword(s):  
High Speed ◽  
Failure Strain ◽  
Damage Model ◽  
Strain Analysis ◽  
High Strength ◽  
Model Parameters ◽  
Outer Diameter ◽  
Water Tank ◽  
Fragment Distribution ◽  
Photonic Doppler Velocimetry

Experiments have been conducted to investigate the fracture and fragmentation characteristics of a liquid phased sintered (LPS) tungsten and high strength steel alloys. Metal cylinders, each of which was 20.32 cm tall and 5.08 cm inner/5.88 cm outer diameter, were explosively driven to failure. Two complimentary types of experiments were conducted in this series to determine input parameters for a related continuum mechanics based modeling effort. Open air experiments utilized ultra-high speed framing photography and a photonic Doppler velocimetry system (PDV). The information from these experiments provided a case wall velocity, relative time of breakup and strain-rate during the stress loading timeframe. Complimentary experiments were conducted in a water tank to perform a soft recovery of the fragments. The fragments were subsequently cleaned, massed, and characterized according to their mass and failure strain distributions. Various methods of analyzing the data (Mott & Weibull distributions) are discussed along with the calibration of the continuum damage model parameters. Results of the failure strain analysis, fragment distribution, and damage model are then supplied for use in subsequent modeling and application designs. Further details of the modeling and simulation approach are outlined in a complimentary set of two papers presented by Lambert [1] and Hopson [2].

Identification strategy influence of elastoplastic behavior law parameters on Gurson–Tvergaard–Needleman damage parameters: Application to DP980 steel

2018 ◽  
Vol 28 (3) ◽  
pp. 427-454 ◽  
Author(s):  
Mustapha Djouabi ◽  
Abdelaziz Ati ◽  
Pierre-Yves Manach
Keyword(s):  
Damage Model ◽  
Weighting Coefficient ◽  
Model Parameters ◽  
Elastoplastic Behavior ◽  
Elastic Plastic ◽  
Hardening Law ◽  
Plastic Modulus ◽  
Gtn Damage Model ◽  
Deep Drawing Test ◽  
Calculation Code

This work adopts elastic–plastic/damage coupling in order to describe tensile behavior with validation on the deep-drawing test of a DP980 Dual Phase steel sheet. The damage model used is the Gurson–Tvergaard–Needleman (GTN model). The hardening laws used are those of Swift (non-saturating law), Voce (saturating law), Hockett-Sherby (saturating law) and the two combined laws Swift/Hockett-Sherby and Swift/Voce. An identifying method for elastic–plastic parameters and GTN damage model parameters is presented using the software modeFRONTIER. This method based on the inverse analysis is also proposed for the identification of weighting coefficient α of the Swift/Hockett-Sherby combined hardening law. Finally, a parametric study was carried out to show that the plastic modulus can be considered as another criterion for the choice of a hardening law. Dependence of the damage model parameters to the hardening law is clearly established. The different behavior laws are introduced via a VUHARD type subroutine in the calculation code Abaqus.

Influence of Geometrical Features of Meso-Defects on Damage Evolution of Metal Structure

2015 ◽  
Vol 723 ◽  
pp. 21-25
Author(s):  
Chao Fan Zhao ◽  
Zhao Xia Li
Keyword(s):  
Aspect Ratio ◽  
Damage Evolution ◽  
Structural Damage ◽  
Volume Fraction ◽  
Failure Process ◽  
Damage Model ◽  
Metal Structure ◽  
Geometrical Features ◽  
Gtn Damage Model ◽  
Defect Volume

To study the failure process of metal structure with meso-defects, RVE (representative volume element) with various initial meso-defects were analyzed by using ABAQUS software, the parameter f (void volume fraction) of GTN damage model was regarded as the criterion of structural damage. The result shows that f increased more obvious with volume of defects for spherical defects with the same shape but different size. When the radius of defects is less than 0.15mm, the influence of defects’ volume on increases of f is clear enough. When the radius is greater than 0.15mm, the effects is diminishing. For ellipsoidal defects with the same volume but different aspect ratio, when the long axis perpendicular to the direction of load, the increased trend of f according to plastic deformation more obvious along with aspect ratio of defects. Apparently, as aspect ratio approaches infinity, f would have the fastest growth. Consequently, the bigger defect volume and aspect ratio, the more conducive for damage evolution of the metal structure.

On the Utilization of Shear Modified GTN Damage Model in Cold Rolling

2015 ◽  
Vol 750 ◽  
pp. 47-50
Author(s):  
Quan Sun ◽  
Da Qian Zan ◽  
Hong Liang Pan ◽  
Jian Jun Chen
Keyword(s):  
Cold Rolling ◽  
Fracture Behavior ◽  
Steel Strip ◽  
Damage Model ◽  
Damage Mechanism ◽  
Rolling Process ◽  
Complex Stress ◽  
Damage And Fracture ◽  
Rolling Experiment ◽  
Gtn Damage Model

Edge cracking is a commonly observed phenomenon in cold rolling process, but researchers appear to be far from fully understanding its failure mechanism due to the complex stress conditions of steel strip under the rolling condition. In this research, the shear modified GTN damage model coupled with Nahshon-Hutchinson shear damage mechanism was applied to investigate the damage and fracture behavior of steel strip in cold rolling. The results show that the shear modified GTN damage model is competent to predict the damage and fracture behavior of steel strip in cold rolling. By comparison to the cold rolling experiment, it presents that the prediction of edge crack occurrence of the shear modified GTN damage model is more accurate than that of the original GTN damage model.

scholarly journals Quantitative Anisotropic Damage Mechanism in a Forged Aluminum Alloy Studied by Synchrotron Tomography and Finite Element Simulations

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Yang Shen ◽  
Thilo F. Morgeneyer ◽  
Jérôme Garnier ◽  
Lucien Allais ◽  
Lukas Helfen ◽  
...  
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Volume Fraction ◽  
Microstructural Analysis ◽  
Damage Model ◽  
Longitudinal Direction ◽  
Damage Mechanism ◽  
Finite Element Simulations ◽  
Synchrotron Tomography ◽  
Micromechanical Damage

A highly anisotropic toughness behavior has been revealed on a forged AA6061 aluminum alloy by toughness tests with CT specimens. The toughness values with specimens loaded on the longitudinal direction are larger than that loaded on the transverse direction due to the anisotropic shape and distribution of coarse precipitates induced by the morphological anisotropy of grains during forging process. Synchrotron radiation computed tomography analysis on as-received material and arrested cracks revealed different fracture modes for the two loading configurations. The damage mechanism has been validated by finite element simulations based on the Gurson–Tvergaard–Needleman micromechanical damage model with different sets of damage parameters for the two loading configurations obtained from quantitative void volume fraction analysis on SRCT data, in situ SEM experiments, and SRCT microstructural analysis.

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