Investigation of the Transition From Plane Strain to Plane Stress in Orthogonal Metal Cutting

2004 ◽  
Author(s):  
Vasant Pednekar ◽  
Vis Madhavan ◽  
Amir H. Adibi-Sedeh
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Plane Stress ◽  
Metal Cutting ◽  
Chip Thickness ◽  
Cutting Conditions ◽  
Depth Of Cut ◽  
Orthogonal Machining ◽  
Strain And Strain Rate ◽  
Plane Strain Deformation

It is widely known that in practical orthogonal machining experiments, interior sections of the deforming material undergo plane strain deformation whereas material near the side faces of the workpiece undergoes plane stress deformation. This study is aimed at investigating the plane strain to plane stress transition using 3D coupled thermo-mechanical finite element analysis of orthogonal machining. The temperature, stress, strain and strain-rate distributions along different planes of the workpiece are analyzed to obtain estimates of the fraction of material undergoing plane strain deformation for different widths of cut. While it is found that the deformation in the mid-section of the workpiece is close to that observed in 2D plane strain simulations, the deformation along the side faces is quite different from that observed in 2D plane stress simulations, due to the constraint imposed upon the material along the sides by the material in the middle. Though the chip thickness along the sides is smaller than the chip thickness in the middle, the strain, strain-rate, and temperature fields along the side face and mid-section are quite similar. This study confirms that accurate maps of temperature, strain and strain-rate in plane strain deformation can be obtained by observing the side faces. It is found that for the cutting conditions used, a width to depth-of-cut ratio of twenty (not ten, as is commonly assumed) results in a close approximation to plane strain deformation through more than 90% of the width of the work material. For a width to depth-of-cut ratio of ten, significant deviations are observed in the stresses, with respect to their corresponding values in plane strain. Recommendations for the width of cut to depth of cut ratio to be used in experiments for other cutting conditions can be developed based upon similar studies.

Numerical Analysis of Plane-Strain Tension Test for Rate-Dependent Solids

1992 ◽  
Vol 59 (3) ◽  
pp. 485-490 ◽  
Author(s):  
P. Tugˇcu
Keyword(s):  
Numerical Analysis ◽  
Strain Rate ◽  
Plane Strain ◽  
Rate Sensitivity ◽  
Tension Test ◽  
Engineering Strain ◽  
Plane Strain Tension ◽  
Rate Dependent ◽  
Strain And Strain Rate ◽  
Strain Rate Hardening

The plane-strain tension test is analyzed numerically for a material with strain and strain-rate hardening characteristics. The effect of the prescribed rate of straining is investigated for an additive logarithmic description of the material strain-rate sensitivity. The dependency to the imposed strain rate so introduced is shown to have a significant effect on several features of the load-elongation curve such as the attainment of the load maximum, the onset of localization, and the overall engineering strain.

Effect of Severe Plastic Deformation in Machining Elucidated via Rate-Strain-Microstructure Mappings

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
S. Shekhar ◽  
S. Abolghasem ◽  
S. Basu ◽  
J. Cai ◽  
M. R. Shankar
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Strain Rate ◽  
Deformation Zone ◽  
Fine Grained ◽  
Orthogonal Machining ◽  
Deformation Parameters ◽  
Strain And Strain Rate ◽  
One To One ◽  
Surface Microstructures

Machining induces severe plastic deformation (SPD) in the chip and on the surface to stimulate dramatic microstructural transformations which can often result in a manufactured component with a fine-grained surface. The aim of this paper is to study the one-to-one mappings between the thermomechanics of deformation during chip formation and an array of resulting microstructural characteristics in terms of central deformation parameters–strain, strain-rate, temperature, and the corresponding Zener–Hollomon (ZH) parameter. Here, we propose a generalizable rate-strain-microstructure (RSM) framework for relating the deformation parameters to the resulting deformed grain size and interface characteristics. We utilize Oxley’s model to calculate the strain and strain-rate for a given orthogonal machining condition which was also validated using digital imaging correlation-based deformation field characterization. Complementary infrared thermography in combination with a modified-Oxley’s analysis was utilized to characterize the temperature in the deformation zone where the SPD at high strain-rates is imposed. These characterizations were utilized to delineate a suitable RSM phase-space composed of the strain as one axis and the ZH parameter as the other. Distinctive one-to-one mappings of various microstructures corresponding to an array of grain sizes and grain boundary distributions onto unique subspaces of this RSM space are shown. Building on the realization that the microstructure on machined surfaces is closely related to the chip microstructure derived from the primary deformation zone, this elucidation is expected to offer a reliable approach for controlling surface microstructures from orthogonal machining.

A Plasticity Problem Involving Plane Strain and Plane Stress Simultaneously: Groove Formation in the Machining of High-Temperature Alloys

1966 ◽  
Vol 88 (2) ◽  
pp. 142-146 ◽  
Author(s):  
M. C. Shaw ◽  
A. L. Thurman ◽  
H. J. Ahlgren
Keyword(s):  
High Temperature ◽  
Plane Strain ◽  
Plane Stress ◽  
Metal Cutting ◽  
Unit Volume ◽  
High Temperature Alloys ◽  
Plastic Analysis ◽  
Plasticity Problem ◽  
Cutting Problem ◽  
Free Edges

Although a plane strain plastic analysis represents a good approximation for the central portion of a metal-cutting chip, plane stress better approximates conditions at the free edges of the chip. Therefore the metal-cutting problem is reexamined using both plane strain and plane stress simultaneously. The analysis indicates that the material at the edges of the chip will become plastic at a lower value of stress than will be required by the central constrained region and that the energy per unit volume at the edges of the chip will be greater than at the center. The consequence of these results is discussed in terms of the wear groove frequently observed on a tool under the free edges of the chip, which is particularly troublesome when machining high-temperature alloys.

On the Difference of Subsurface Deformation Obtained by Image Correlation Technique From That of Plane Strain Deformation in Orthogonal Metal Cutting

2016 ◽  
Author(s):  
Dong Zhang ◽  
Xiao-Ming Zhang ◽  
Han Ding
Keyword(s):  
Plane Strain ◽  
Inclination Angle ◽  
Metal Cutting ◽  
Side Surface ◽  
Image Correlation ◽  
Subsurface Deformation ◽  
Plane Strain Deformation ◽  
Orthogonal Metal Cutting ◽  
Angle Method ◽  
Side Flow

Subsurface deformation in orthogonal metal cutting process is nowadays widely determined by image correlation techniques. To get clearer images of the cutting process, two methods were usually adopted to reduce workpiece material side flow in the literature. One is inducing a weak inclination angle of the cutting tool; the other is to restrict material side flow by a piece of thick glass. However, the differences between the subsurface deformation determined by observing the side surfaces in these two methods and that of plane strain deformation has not been studied yet. Therefore, this paper aims to study the differences of subsurface deformation obtained by these two methods quantitatively through numerical methods. It is found that the restrict side flow method surpasses the inducing an inclination angle method; inducing an inclination angle method will produce larger discrepancy than the side surface of typical orthogonal cutting which stands for observing the side surface directly. Besides, restrict material side flow method surpasses inducing an inclination angle method in the aspect of strain distribution across the width direction. To reduce the differences further, a new method called split-workpiece method based on the bonded-interface technique is proposed in this paper. To validate the effectiveness of this method, numerical comparisons between the subsurface deformation produced by the proposed method and that of the plane strain deformation are made. The results show that the subsurface deformation produced by the proposed method is much closer to that of plane strain deformation than the previous two methods.

scholarly journals Optimization of process parameters on commercial mild steel using taguchi technique

2017 ◽  
Vol 7 (1.1) ◽  
pp. 138 ◽  
Author(s):  
V. Jaiganesh ◽  
B. Yokesh Kumar ◽  
P. Sevvel ◽  
A.J. Balaji
Keyword(s):  
Surface Roughness ◽  
Mild Steel ◽  
Metal Cutting ◽  
Metal Removal ◽  
Removal Rate ◽  
Chip Thickness ◽  
Critical Factor ◽  
Thickness Ratio ◽  
Depth Of Cut ◽  
Versus Input

In the present scenario of bulk manufacturing where Metal Removal Rate (MRR), Chip Thickness Ratio (CTR) and Surface Roughness (SR) is of significant importance in manufacturing the component using CNC (computer numerical controlled) machines. Nine experiments were conducted based on orthogonal array. General linear model has been generated for all the three output parameters such as (MRR, Chip Thickness Ratio surface roughness) versus input parameters (speed, time, depth of cut). The statistical method called the analysis of variance (ANOVA) is applied to find the critical factor. The Main effects of S/N ratio values are found and plotted in the form of graph. The optimized value is found for speed, time, and depth of cut by using “MINITAB” software. By using this optimized value the efficient metal cutting can be done in commercial mild steel.

Numerical Investigation of Two-Dimensional Thermally Assisted Ductile Regime Milling of Brittle Materials

2014 ◽  
Author(s):  
Jianfeng Ma ◽  
Xianchen Ge ◽  
Shuting Lei
Keyword(s):  
Chip Thickness ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Uncut Chip Thickness ◽  
Thermal Boundary Conditions ◽  
Orthogonal Machining ◽  
Preheating Temperature ◽  
Ductile Regime Machining ◽  
Critical Depth Of Cut

This study investigates the effects of different variables (preheating temperature, edge radius, and rake angle) on ductile regime milling of a bioceramic material known as nanohydroxyapatite (nano-HAP) using numerical simulation. AdvantEdge FEM Version 6.1 is used to conduct the simulation of 2D milling mimicked by orthogonal machining with varying uncut chip thickness. Thermal boundary conditions are specified to approximate laser preheating of the work material. Based on the pressure-based criterion for ductile regime machining, the dependence of critical depth of cut on cutting conditions is investigated using Tecplot 360. It is found that as uncut chip thickness decreases, the critical depth of cut decreases. In addition, the critical depth of cut increases as the negativity of rake angle and/or preheating temperature increase.

Finite Element Modelling and Analysis of Cutting-Direction Burr Formation

2008 ◽  
Vol 392-394 ◽  
pp. 88-92
Author(s):  
Xiao Wang ◽  
H. Yan ◽  
C. Liang ◽  
B. Wu ◽  
Hui Xia Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Metal Cutting ◽  
Chip Thickness ◽  
Element Model ◽  
Rake Angle ◽  
Burr Formation ◽  
Workpiece Material ◽  
Orthogonal Machining ◽  
Cutting Direction

To prevent or reduce the formation of burr efficiently in metal cutting, it is necessary to reveal the burr formation mechanism. A finite element model of cutting-direction burr formation in orthogonal machining was presented in this paper. The simulation of the burr formation process was conducted. Undeformed chip thickness, rake angle, rounded cutting edge radius and workpiece material were included in cutting conditions, whose influences on burr formation were investigated, according to the simulation results. By comparing the results of the simulation and the experiment, good consistency is achieved which proves that the finite element model of burr formation in this paper is significant and effective to predict burr formation.

On the Plane Stress to Plane Strain Transition Across the Shear Zone in Metal Cutting

1988 ◽  
Vol 110 (4) ◽  
pp. 322-325 ◽  
Author(s):  
B. E. Klamecki ◽  
S. Kim
Keyword(s):  
Plane Strain ◽  
Shear Zone ◽  
Plane Stress ◽  
Central Region ◽  
Chip Formation ◽  
Metal Cutting ◽  
High Strain ◽  
Surface Characteristics ◽  
Workpiece Material ◽  
Element Analysis

The effects of the stress state transition from plane stress at the workpiece surface to plane strain in the central region of the chip formation zone were studied. A finite element analysis of the incipient chip formation process was performed. The model included heat generation and temperature induced workpiece material property changes. The primary result is that the unique high strain, high strain rate, large free surface characteristics of the metal cutting process can result in qualitatively different deformation behavior across the shear zone. Temperatures are higher in the regions near the surface of the workpiece than in the central region. In extreme cases, this will result in strain hardening behavior in the plain strain regions and thermal softening of the work material near the surface.

Analytical Calculation of the True Equivalent Chip Thickness for Cutting Tools and its Influence on the Calculated Tool Life

2012 ◽  
Vol 576 ◽  
pp. 80-86 ◽  
Author(s):  
Jan Eric Ståhl ◽  
Fredrik Schultheiss
Keyword(s):  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Analytical Calculation ◽  
Chip Thickness ◽  
Depth Of Cut ◽  
Nose Radius ◽  
Chip Area ◽  
Vital Importance ◽  
Finishing Machining

A majority of the established systems for determination and optimization of cutting data are based on Woxén’s equivalent chip thickness, heW. In metal cutting theory and models, the equivalent chip thickness is of vital importance when the depth-of-cut apis in the same order or smaller than the nose radius r. Woxén made considerable simplifications in his chip area model, that form the basis for calculations of the equivalent chip thickness. Basic mathematical solutions, e.g. describing the chip area on circular inserts, are lacking. This article describes the geometrical implications when machining with round inserts. The error in Woxén’s equivalent chip thickness is largest when the depth-of-cut is less than ¼ of the nose radius and are up to 40 % wrong for some combinations of cutting data in the finishing range. The presented results explain the difficulties in getting a good validity in the models used to calculate tool life in finishing machining. The error leads to an underrating of the tool load in many machining situations

Microstructure and Texture in an Alpha/Beta Titanium Alloy and their Impact on Mechanical Response

2007 ◽  
Vol 539-543 ◽  
pp. 3589-3594
Author(s):  
W.J. Evans ◽  
F.R. Eng
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Titanium Alloys ◽  
Plane Strain ◽  
Basal Plane ◽  
Mechanical Response ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Strain And Strain Rate ◽  
Alpha Beta

The paper explores texture in the titanium alloys Ti-6-4 and Ti 550. It illustrates how texture evolves under plane strain compression in Ti-6-4. This evolution is dependent on temperature, degree of reduction (strain) and strain rate. Rolled (Ti-6-4) and forged (Ti 550) variants with different textures are then examined under tension and torsion loading in relation to their monotonic and fatigue response. Correlation of the observations with regard to orientation of the basal plane is demonstrated.

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