Study of a modified ECAP die for producing nanostructured Al6060 alloy using 3D finite element simulation

2016 ◽  
Vol 1818 ◽  
Author(s):  
M. A. González-Lozano ◽  
P. Ponce-Peña ◽  
M.A. Escobedo-Bretado ◽  
R.H. Lara-Castro ◽  
B. X. Ochoa-Salazar
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Severe Plastic Deformation ◽  
Tensile Stress ◽  
Deformation Zone ◽  
Plastic Deformation Zone ◽  
Element Analysis ◽  
Ecap Processing ◽  
Angular Pressing ◽  
Element Simulation

ABSTRACTUsing Finite Element Method (FEM) simulations is possible to study the homogeneity of deformation in the Equal Channel Angular Pressing (ECAP) process. In this work an investigation about the influence of a modified die on strain distribution in an ecaped Al6060 alloy was carried out. Due to that, tensile stress occurs in the vicinity of upper surface of the specimen in the severe plastic deformation zone, which increases the cracking and fracture tendency of the specimen and impedes further ECAP processing, the conventional ECAP die was modified to eliminate the tensile stress and enhance the compressive stress in the severe plastic deformation zone and reducing the cracking and fracture tendency of the specimen. Finite element analysis demonstrated that the stress state changes from tensile to strongly compressive when using the modified die. The aim of this study is to evaluate the advantages/disadvantages of the modified ECAP die and processing conditions.

MULTI-SCALE FINITE ELEMENT SIMULATION OF SEVERE PLASTIC DEFORMATION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1621-1626
Author(s):  
HYOUNG SEOP KIM
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Severe Plastic Deformation ◽  
Constitutive Model ◽  
Dislocation Cell ◽  
Ultrafine Grain ◽  
Angular Pressing ◽  
Element Simulation ◽  
Ultrafine Grain Size ◽  
Ultrafine Grained

The technique of severe plastic deformation (SPD) enables one to produce metals and alloys with an ultrafine grain size of about 100 nm and less. As the mechanical properties of such ultrafine grained materials are governed by the plastic deformation during the SPD process, the understanding of the stress and strain development in a workpiece is very important for optimizing the SPD process design and for microstructural control. The objectives of this work is to present a constitutive model based on the dislocation density and dislocation cell evolution for large plastic strains as applied to equal channel angular pressing (ECAP). This paper briefly introduces the constitutive model and presents the results obtained with this model for ECAP by the finite element method.

A critical examination of the relationship between plastic deformation zone size and Young's modulus to hardness ratio in indentation testing

2006 ◽  
Vol 21 (10) ◽  
pp. 2617-2627 ◽  
Author(s):  
J. Chen ◽  
S.J. Bull
Keyword(s):  
Finite Element Analysis ◽  
Plastic Deformation ◽  
Finite Element ◽  
Young’S Modulus ◽  
Deformation Zone ◽  
Young's Modulus ◽  
Critical Examination ◽  
Analytical Relationship ◽  
Plastic Deformation Zone ◽  
Element Analysis

Existing indentation models (both analytical models and numerical analysis) show a linear relationship between δr/δm and H/Er, where δr and δm are the residual and maximum indentation depth, and Er and H are the reduced Young's modulus and hardness of the test material. Based on the analysis of Oliver and Pharr, a new relationship between δr/δm and H/Er has been derived in a different way without any additional assumptions, which is nonlinear, and this has been verified by finite element analysis for a range of bulk materials. Furthermore, this new relationship for residual depth is used to derive an analytical relationship for the radius of the plastic deformation zone Rp in terms of the residual depth, Young’s modulus, and hardness, which has also been verified by finite element simulations for elastic perfectly plastic materials with different work hardening behavior. The analytical model and finite element simulation confirms that the conventional relationship used to determine Rp developed by Lawn et al. overestimates the plastic deformation, especially for those materials with high E/H ratio. The model and finite element analysis demonstrate that Rp scales with δr, which is sensible given the self-similarity of the indentations at different scales, and that the ratio of Rp/δr is nearly constant for materials with different E/H, which contradicts the conventional view.

Finite Element Simulation of Aluminum ECAP Material Flow

2013 ◽  
Vol 423-426 ◽  
pp. 267-270
Author(s):  
Jian Hui Li ◽  
Zu Jian Yu ◽  
Da Zhi Xiao ◽  
Li Ping Zhang
Keyword(s):  
Finite Element ◽  
Material Flow ◽  
Maximum Principal Stress ◽  
Metallic Materials ◽  
Rigid Plastic ◽  
Ecap Processing ◽  
Angular Pressing ◽  
Fine Grain ◽  
Corner Flow ◽  
Element Simulation

To enhancing strength and toughness of metals, severe plastic deformation (SPD) grain refinement was a typical method. As one of the SPD method, equal channel angular pressing is an effective method in fabricating ultra-fine grain metallic materials. In this paper, the rigid-plastic finite element method was used to analyze the aluminum alloy ECAP processing, to reveal the material flow character and its effect on microstructure evolution. The simulation results were agreed with plastic mechanics and experiment well, and it was shown that distribution of maximum principal stress was not uniform, material located at the front-end of sample flow easily and material located at the top of die channel corner flow difficultly.

scholarly journals Topology Optimization of Elastoplastic Behavior Conditions by Selectively Suppressing Plastic Work

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 2062
Author(s):  
Eun-Ho Lee ◽  
Tae-Hyun Kim
Keyword(s):  
Plastic Deformation ◽  
Topology Optimization ◽  
Elastic Deformation ◽  
Deformation Zone ◽  
Strain Energy ◽  
Optimization Problems ◽  
Elastic Stiffness ◽  
Plastic Work ◽  
Plastic Deformation Zone ◽  
Element Analysis

This work conducted topology optimization with an implicit analysis of elastoplastic constitutive equation in order to design supporting structures for unexpected heavy loading conditions. In this topology optimization model, plastic work was extracted from strain energy and selectively employed in the objective function according to deformation mode. While strain energy was minimized in elastic deformation areas, in elastoplastic deformation areas, the plastic work was minimized for the purpose of suppressing plastic deformation. This method can focus on suppressing plastic strain in the plastic deformation zone with maintaining elastic stiffness in the elastic deformation zone. These formulations were implemented into MATLAB and applied to three optimization problems. The elastoplastic optimization results were compared to pure elastic design results. The comparison showed that structures designed with accounting for plastic deformation had a reinforced area where plastic deformation occurs. Finally, a finite element analysis was conducted to compare the mechanical performances of structures with respect to the design method.

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