A Methodology to Determine Work Material Flow Stress and Tool-Chip Interfacial Friction Properties by Using Analysis of Machining

2004 ◽  
Author(s):  
Tug˘rul O¨zel ◽  
Erol Zeren
Keyword(s):  
Flow Stress ◽  
Material Flow ◽  
Orthogonal Cutting ◽  
Material Model ◽  
Interfacial Friction ◽  
Frictional Stress ◽  
Rake Face ◽  
Friction Characteristics ◽  
Work Material ◽  
1045 Steel

In this paper, we develop a methodology to determine flow stress at the machining regimes and friction characteristics at the tool-chip interface from the results of orthogonal cutting tests. We utilize metal cutting analysis originally developed by late Oxley and present some improvements. We also evaluate several temperature models in calculating the average temperatures at primary and secondary deformation zones and present comparisons with the experimental data obtained for AISI 1045 steel through assessment of machining models (AMM) activity. The proposed methodology utilizes measured forces and chip thickness obtained through a basic orthogonal cutting test. We conveniently determine work material flow stress at the primary deformation zone and the interfacial friction characteristics along tool rake face. Calculated friction characteristics include parameters of the normal and frictional stress distributions on the rake face. Determined flow stress data from orthogonal cutting tests is combined with the flow stress measured through split-hopkinson pressure bar (SHPB) tests and the Johnson-Cook work material model is obtained. Therefore, with this methodology, we extend the applicability of Johnson-Cook work material model to machining regimes.

A Methodology to Determine Work Material Flow Stress and Tool-Chip Interfacial Friction Properties by Using Analysis of Machining

2005 ◽  
Vol 128 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Tuğrul Özel ◽  
Erol Zeren
Keyword(s):  
Flow Stress ◽  
Normal Stress ◽  
Material Flow ◽  
Orthogonal Cutting ◽  
Material Model ◽  
Interfacial Friction ◽  
Rake Face ◽  
Friction Characteristics ◽  
Work Material ◽  
1045 Steel

In this paper, we develop a methodology to determine flow stress at the machining regimes and friction characteristics at the tool-chip interface from the results of orthogonal cutting tests. We utilize metal cutting analysis originally developed by late Oxley and present some improvements. We also evaluate several temperature models in calculating the average temperatures at primary and secondary deformation zones and present comparisons with the experimental data obtained for AISI 1045 steel through assessment of machining models (AMM) activity. The proposed methodology utilizes measured forces and chip thickness obtained through a basic orthogonal cutting test. We conveniently determine work material flow stress at the primary deformation zone and the interfacial friction characteristics along the tool rake face. Calculated friction characteristics include parameters of the normal and frictional stress distributions on the rake face that are maximum normal stress σNmax, power exponent for the normal stress distribution, a, length of the plastic contact, lp, length of the tool-chip contact, lc, the average shear flow stress at tool-chip interface, kchip, and an average coefficient of friction, μe, in the sliding region of the tool-chip interface. Determined flow stress data from orthogonal cutting tests is combined with the flow stress measured through split-hopkinson pressure bar (SHPB) tests and the Johnson-Cook work material model is obtained. Therefore, with this methodology, we extend the applicability of a Johnson-Cook work material model to machining regimes.

scholarly journals Modelling Texturised Cast Structures in the Forging of Superalloys

2011 ◽  
Vol 278 ◽  
pp. 210-215
Author(s):  
Jan Terhaar ◽  
Nikolaus Blaes ◽  
Dieter Bokelmann ◽  
Hendrik Schafstall
Keyword(s):  
Flow Stress ◽  
Material Flow ◽  
Cylindrical Specimen ◽  
Material Model ◽  
Growth Direction ◽  
Solidification Structure ◽  
Vacuum Arc ◽  
Correct Prediction ◽  
Dendrites Growth ◽  
Stress Dependency

The main objective of remelting processes commonly used in the production of super¬alloys is to obtain a columnar dendritic solidification structure throughout the whole ingot. Besides reduced microsegregation, this cast structure features a preferred orientation, which is depending on the primary dendrites’ growth direction and therefore closely related to the ingot’s pool shape. As a result, non-isotropic material behaviour can be observed during initial forging operations. Since the correct prediction of material flow is a prerequisite for the further analysis of forging processes by means of numerical simulation, the solidification texture’s influence on plastic flow was accounted for by the application of an anisotropic material model. The model according to Barlat was used to scale the flow stress with respect to the crystal orientations observed in the examination of vacuum arc remelted alloy 718, thereby considering the flow stress’ dependency on strain, strain rate and temperature. The parameters defining the material's anisotropy could be determined by the upsetting of cylindrical specimen from a remelted ingot.

The Effect of Material Flow Stress on Analytical Simulation of Machining

2010 ◽  
Vol 29-32 ◽  
pp. 1809-1814
Author(s):  
Bing Lin Li ◽  
Ling Ling ◽  
Yu Jin Hu ◽  
Xue Lin Wang
Keyword(s):  
Flow Stress ◽  
Shear Zone ◽  
Analytical Model ◽  
Material Flow ◽  
Model Simulation ◽  
Orthogonal Cutting ◽  
Shear Plane ◽  
Thermomechanical Model ◽  
Workpiece Material ◽  
Flow Stress Data

The flow stress data of the workpiece are extremely crucial for the cutting simulation. The study shows how the input data affect the analytical predictions of cutting force and temperature. The Johnson-Cook material model is used to represent workpiece flow stress in the primary shear zone. A thermomechanical model of orthogonal cutting is proposed based on the main shear plane divides the primary shear zone into two unequal parts. Five different sets of workpiece material flow stress data used in the Johnson-Cook’s constitutive equation are chosen and make the sensitivity analysis for analytical model. Simulation results were compared to orthogonal cutting test data from the available literature, and find the effects of flow stress on analytical model was different from that for finite element model.

Identification of Flow Stress Applicable for FEM Simulation of Orthogonal Cutting Process

2014 ◽  
Vol 625 ◽  
pp. 378-383 ◽  
Author(s):  
Norfariza Wahab ◽  
Yumi Inatsugu ◽  
Satoshi Kubota ◽  
Soo Young Kim ◽  
Hiroyuki Sasahara
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Fem Simulation ◽  
Material Model ◽  
Cutting Process ◽  
Machining Parameters ◽  
High Speed Cutting ◽  
Cutting Test

Nowadays, numerical simulation technique is very popular to estimate and predict the machining parameters such as cutting forces, stresses distribution, temperature and tool wear. The objective of this study is to determine the 0.45%C steel (JIS S45C) flow stress value under high strain rate and temperature. The Johnson and Cook (JC) material model is used as a constitutive equation to describe the high speed cutting process. Compression test and orthogonal cutting test were carried out in order to obtain the required parameters in JC model. Inverse calculation method was used to determine the strain rate and temperature dependency parameter based on several cutting conditions. As a result, validity of verification of method was completed and the flow stress of S45C had been evaluated.

scholarly journals A Numerical-Experimental Study on Orthogonal Cutting of AISI 1045 Steel and Ti6Al4V Alloy: SPH and FEM Modeling with Newly Identified Friction Coefficients

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1683
Author(s):  
Mohamadreza Afrasiabi ◽  
Jannis Saelzer ◽  
Sebastian Berger ◽  
Ivan Iovkov ◽  
Hagen Klippel ◽  
...  
Keyword(s):  
Metal Cutting ◽  
Experimental Validation ◽  
Orthogonal Cutting ◽  
Thermal Loads ◽  
Rake Face ◽  
Friction Coefficients ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel ◽  
Face Temperature

Numerical simulation of metal cutting with rigorous experimental validation is a profitable approach that facilitates process optimization and better productivity. In this work, we apply the Smoothed Particle Hydrodynamics (SPH) and Finite Element Method (FEM) to simulate the chip formation process within a thermo-mechanically coupled framework. A series of cutting experiments on two widely-used workpiece materials, i.e., AISI 1045 steel and Ti6Al4V titanium alloy, is conducted for validation purposes. Furthermore, we present a novel technique to measure the rake face temperature without manipulating the chip flow within the experimental framework, which offers a new quality of the experimental validation of thermal loads in orthogonal metal cutting. All material parameters and friction coefficients are identified in-situ, proposing new values for temperature-dependent and velocity-dependent friction coefficients of AISI 1045 and Ti6Al4V under the cutting conditions. Simulation results show that the choice of friction coefficient has a higher impact on SPH forces than FEM. Average errors of force prediction for SPH and FEM were in the range of 33% and 23%, respectively. Except for the rake face temperature of Ti6Al4V, both SPH and FEM provide accurate predictions of thermal loads with 5–20% error.

Thermoviscoplastic modelling of drilling: Twist drills

2008 ◽  
Vol 222 (3) ◽  
pp. 403-411 ◽  
Author(s):  
A Nayebi ◽  
H Vaghefpour
Keyword(s):  
Cutting Forces ◽  
Material Flow ◽  
Thrust Force ◽  
Orthogonal Cutting ◽  
Material Model ◽  
Thermomechanical Properties ◽  
Twist Drill ◽  
Viscoplastic Material ◽  
Al 7075 ◽  
Twist Drills

In this paper, a viscoplastic material model is proposed for drilling of metals. An analytical model is developed for predicting thrust force and torque in drilling with a twist drill. The thermomechanical properties are taken into consideration to describe the material flow in the primary shear zone and at the element—chip interface. The Johnson—Cook model is used. A temperature friction law is introduced. The approach is based on representing the cutting forces along the cutting lips as a series of oblique elements. Similarly, cutting in the chisel region is treated as orthogonal cutting with different speeds depending on the radial location. The section forces obtained by the model are combined to determine the overall thrust force and drilling torque. The results of the model are compared with the experimental results obtained by Bagci and Ozcelik in 2006 on Al 7075-T651.

scholarly journals An Explanation of the Apparent Bridgman Effect in Merchant’s Orthogonal Cutting Results

1967 ◽  
Vol 89 (3) ◽  
pp. 549-555 ◽  
Author(s):  
P. L. B. Oxley ◽  
M. J. M. Welsh
Keyword(s):  
Shear Strength ◽  
Flow Stress ◽  
Strain Rate ◽  
Hydrostatic Stress ◽  
Orthogonal Cutting ◽  
Shear Angle ◽  
Experimental Results ◽  
Variable Flow ◽  
Rate Dependent ◽  
Work Material

In Merchant’s modified shear angle solution, it is assumed following Bridgman that the shear strength of the work material is a function of the hydrostatic stress. Although Merchant’s experimental results confirm the assumed relation, subsequent workers have failed to obtain such agreement. In this paper, it is shown that Merchant’s results can be explained independently of the Bridgman effect by considering the variable flow stress properties of the work material, which are strain-rate dependent.

New Thermal Issues on the Modelling of Tool-Workpiece Interaction: Application to Dry Cutting of AISI 1045 Steel

2011 ◽  
Vol 223 ◽  
pp. 286-295 ◽  
Author(s):  
Cédric Courbon ◽  
Tarek Mabrouki ◽  
Joël Rech ◽  
Denis Mazuyer ◽  
Enrico D'Eramo
Keyword(s):  
Heat Flux ◽  
Hot Spot ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Contact Length ◽  
Dry Cutting ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel ◽  
Coated Carbide

The present work proposes to enhance the thermal interface denition in Finite Element (FE) simulations of machining. A user subroutine has been developed in Abaqus/Explicit © to implement a new experimentally-based heat partition model extracted from tribological tests. A 2D Arbitrary-Lagragian-Eulerian (ALE) approach is employed to simulate dry orthogonal cutting of AISI 1045 steel with coated carbide inserts. Simulation results are compared to experimental ones over a whole range of cutting speeds and feed rates in terms of average cutting forces, chip thickness, tool chip contact length and heat flux. This study emphasizes that heat transfer and temperature distribution in the cutting tool are drastically in uenced by the thermal formulation used at the interface. Consistency of the numerical results such as heat flux transmitted to the tool, peak temperature as well as hot spot location can be denitively improved.

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