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.

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.

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.

Blanking of Plastic Forming Simulation and Analysis Based on the DEFORM

2013 ◽  
Vol 300-301 ◽  
pp. 128-132
Author(s):  
Wan Shun Wang ◽  
Yan Wang ◽  
Qiu Ping Wang
Keyword(s):  
Numerical Simulation ◽  
Plastic Deformation ◽  
Deformation Zone ◽  
Shear Fracture ◽  
Plastic Deformation Zone ◽  
Element Analysis ◽  
Forming Simulation ◽  
Plastic Forming ◽  
Computer Based ◽  
Dynamic Numerical Simulation

Plastic forming of metal material is a complex process. To predict and explore the forming law of these issues must be based on computer-based numerical methods. In this article, the shearing step of a textile knotted knife is studied. With the application of the DEFORM finite element analysis software, we make a dynamic numerical simulation of shear fracture on the tool sheet. After analyzing material’s stress and strain distribution in the plastic deformation zone and plastic flow vector in sheet deformation zone, the variable distribution curve of strain state can be obtained. And by comparing with the simulation experiment, acceptable product can be received. Through the numerical simulation, we can have an intuitive understanding of the plastic deformation process of this sheet, in the mean time; deeply understand the mechanism of plastic deformation. The numerical analysis method and the selection of the parametric have a significance of guiding and reference to the quality improvement of knotted knife products.

Research of stamping of unequal channel bars. Part 4. Deformed state of the workpiece when extruding channels. 2. Deformations under the punch end

2021 ◽  
pp. 53-57
Author(s):  
A.L. Vorontsov
Keyword(s):  
Plastic Deformation ◽  
Plane Strain ◽  
Deformation Zone ◽  
Plastic Deformation Zone ◽  
Die Forging ◽  
Deformed State

Determination of the deformed state of the workpiece at free extrusion of channels is considered. Formulas are obtained for determining the accumulated deformations at a given point of the plastic deformation zone and extruded walls of the product for any punch working stroke. Keywords: die forging, extrusion, misalignment, punch, matrix, plane strain, accumulated deformations, hardening. [email protected]

Nanoindentation Characterization of Single-Crystal Silicon With Oxide Film

2021 ◽  
Author(s):  
Lianmin Yin ◽  
Yifan Dai ◽  
Hao Hu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Oxide Film ◽  
Single Crystal ◽  
Deformation Zone ◽  
Single Crystal Silicon ◽  
Plastic Deformation Zone ◽  
Crystal Silicon ◽  
Ultra Precision

Abstract In order to obtain ultra-smooth surfaces of single-crystal silicon in ultra-precision machining, an accurate study of the deformation mechanism, mechanical properties, and the effect of oxide film under load is required. The mechanical properties of single-crystal silicon and the phase transition after nanoindentation experiments are investigated by nanoindentation and Raman spectroscopy, respectively. It is found that pop-in events appear in the theoretical elastic domain of single-crystal silicon due to the presence of oxide films, which directly leads the single crystal silicon from the elastic deformation zone into the plastic deformation zone. In addition, the mechanical properties of single-crystal silicon are more accurately measured after it has entered the full plastic deformation.

OBSERVATION OF PLASTIC DEFORMATION ZONE WITH ACOUSTIC MICROSCOPE

1988 ◽  
Vol 4 (2-3) ◽  
pp. 55-55 ◽  
Author(s):  
Isao ISHIKAWA ◽  
Hiroshi KANDA ◽  
Kageyoshi KATAKURA ◽  
Takuya SENBA ◽  
Yasuhiro TANI ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Deformation Zone ◽  
Plastic Deformation Zone ◽  
Acoustic Microscope
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