Research of Formation Mechanics on Nanostructured Chips by Multi-Deformations Based on Finite Element Method

2014 ◽  
Vol 989-994 ◽  
pp. 352-355
Author(s):  
C.L. Wu ◽  
Z.R. Wang ◽  
Wen Zhang
Keyword(s):  
Finite Element Method ◽  
Plastic Deformation ◽  
Finite Element ◽  
Large Strain ◽  
Effective Strain ◽  
Longitudinal Section ◽  
Rake Angle ◽  
Governing Parameter ◽  
Cutting Velocity ◽  
Mean Strain

Formation of chip is a typical severe plastic deformation progress in machining which is only single deformation stage. The rake angle of tool is governing parameter to create large strain imposed in the chip. Effect of rake angle and deformation times on effective strain, mean strain, strain variety and strain rate imposed in the chip are researched respectively. The result of simulation have shown that the chip with large strain and better uniform of strain along the longitudinal section of chip can be produced with negative rake angle at some lower cutting velocity by multi-deformations in large strain machining.

Effect of Machining Parameters on Deformation Field in Machining by Finite Element Method

2011 ◽  
Vol 80-81 ◽  
pp. 942-945
Author(s):  
C.L. Wu ◽  
Z.R. Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cutting Force ◽  
Large Strain ◽  
Effective Strain ◽  
High Hardness ◽  
Rake Angle ◽  
Machining Parameters ◽  
Cutting Velocity ◽  
Element Method

Formation of chip is a typical severe plastic deformation progress in machining which is only single deformation stage. The large strain, low temperature and deformation force are the major premises to create significant microstructure refinement in metals and alloys. A finite element method was developed to characterize the distribution of strain, temperature and cutting force. Effects of rake angle, cutting velocity and friction on effective strain, cutting force imposed in the chip are researched and the conditions which lead to the large stain deformation in machining are highlighted. The results of simulation have shown that chip materials with ultrafine grained and high hardness can be produced with negative tool rake angle at some lower cutting velocity.

Deformation Characteristics of Ultra-Fine Grained Al6061 Chip in Machining by Finite Element Method

2010 ◽  
Vol 44-47 ◽  
pp. 2931-2934
Author(s):  
Chun Ling Wu ◽  
Bang Yan Ye
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Coefficient Of Friction ◽  
Metal Cutting ◽  
High Hardness ◽  
Rake Angle ◽  
Fine Grained ◽  
The Coefficient Of Friction ◽  
Cutting Velocity ◽  
Element Method

Ultra-fine grained chips with higher hardness and strength than bulk can be produced by severe plastic deformation during orthogonal metal cutting. A finite element method was developed to characterize the distribution of stress, strain, strain rate and temperature in the deformation area at different rake angles and cutting velocities. The coefficient of friction in the tool-chip interface is approximately obtained according model of mean coefficient of friction which is based on experiments in any machining conditions. The formation mechanics of ultra-fine grained chip is discussed and effect of rake angle on microstructure of chips is highlighted. The results of experiment and modeling have shown that chip materials with ultra-fine grained and high hardness can be produced with more negative tool rake angle at some lower cutting velocity.

Computation on continuous grain refinement in AA1050 aluminum during repetitive tube expansion and shrinking technique

2015 ◽  
Vol 232 (4) ◽  
pp. 307-318
Author(s):  
H Jafarzadeh ◽  
K Abrinia
Keyword(s):  
Finite Element Method ◽  
Plastic Deformation ◽  
Grain Size ◽  
Finite Element ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Half Cycle ◽  
Tube Expansion ◽  
Element Method

The microstructure evolution during recently developed severe plastic deformation method named repetitive tube expansion and shrinking of commercially pure AA1050 aluminum tubes has been studied in this paper. The behavior of the material under repetitive tube expansion and shrinking including grain size and dislocation density was simulated using the finite element method. The continuous dynamic recrystallization of AA1050 during severe plastic deformation was considered as the main grain refinement mechanism in micromechanical constitutive model. Also, the flow stress of material in macroscopic scale is related to microstructure quantities. This is in contrast to the previous approaches in finite element method simulations of severe plastic deformation methods where the microstructure parameters such as grain size were not considered at all. The grain size and dislocation density data were obtained during the simulation of the first and second half-cycles of repetitive tube expansion and shrinking, and good agreement with experimental data was observed. The finite element method simulated grain refinement behavior is consistent with the experimentally obtained results, where the rapid decrease of the grain size occurred during the first half-cycle and slowed down from the second half-cycle onwards. Calculations indicated a uniform distribution of grain size and dislocation density along the tube length but a non-uniform distribution along the tube thickness. The distribution characteristics of grain size, dislocation density, hardness, and effective plastic strain were consistent with each other.

Effect of the Friction Coefficient on Large Strain Extrusion Machining

2013 ◽  
Vol 273 ◽  
pp. 138-142 ◽  
Author(s):  
Ping Lin ◽  
Zi Chun Xie ◽  
Qing Li
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Nanostructured Materials ◽  
Deformation Behavior ◽  
Large Strain ◽  
Effective Strain ◽  
Finite Element Simulations ◽  
Friction Coefficients ◽  
Simulation Results

The present study focused on the influence of the friction coefficient on the deformation behavior in large strain extrusion machining (LSEM). A series of simulation results of effective strain were obtained under different friction coefficients by conducting finite element simulations with a FEM code. The results show that LSEM can produce different effective strains by changing the friction coefficients, thus enabling the fabrication of bulk nanostructured materials. An analysis of the variation of effective strain through the chip demonstrated that the chip deformed much more inhomogeneously when the friction coefficient became larger. The obtained results can offer valuable guidelines for later LSEM studies.

Mean Strain Effect on Crack Initiation Lives for Notched Specimens Under Biaxial Nonproportional Loading Paths

1997 ◽  
Vol 119 (1) ◽  
pp. 104-112 ◽  
Author(s):  
Ming-Chuen Yip ◽  
Yi-Ming Jen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Initiation ◽  
Strain Effect ◽  
Nonproportional Loading ◽  
Notched Specimens ◽  
Loading Paths ◽  
The Mean ◽  
Mean Strain ◽  
Element Method

This paper discusses the mean strain effect on the crack initiation lives for notched specimens under biaxial nonproportional loading paths. Elastic-plastic finite element method was used to evaluate the local stresses and strains. Several prediction models related to the mean stress/strain effect were employed to correlate the experimental results with reference fatigue data for smooth specimens. It is found that Fatemi-Socie model gives good prediction for the present research with the assistance of finite element method. The stress behavior in this deflection-controlled tests is discussed in this study, and the failure surfaces are also examined after tests.

Finite Element Simulation of Cyclic Channel Die Compression with Route A

2010 ◽  
Vol 44-47 ◽  
pp. 1300-1304
Author(s):  
Feng Jian Shi ◽  
Tao Xu ◽  
Sheng Lu ◽  
Lei Gang Wang
Keyword(s):  
Finite Element ◽  
Large Strain ◽  
Effective Strain ◽  
Central Zone ◽  
Peripheral Zone ◽  
Linear Increase ◽  
Rigid Plastic ◽  
Compression Load ◽  
Fine Grained ◽  
Two Stages

In this paper, effective strain and load were simulated by rigid-plastic finite element method (FEM) during cyclic channel die compression (CCDC) with route A, and the optical microstructure was observed. The results show that large strain can be accumulated in the material by CCDC. The load variation includes two stages, slowly linear increase and rapid increase. At the end of the CCDC, the compression load rises rapidly. Apart from the edges of the specimen, the effective strain is higher in the central region and lower at the surrounding region. The effective strain gradient increases with the number of compression. Grain refinement at the central zone is faster due to the strain inhomogeneity. But the peripheral zone is also refined with the number of CCDC. This illustrates CCDC is a promising method for producing bulk ultra-fine grained materials.

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