Identification of Material Constitutive Laws for Machining—Part II: Generation of the Constitutive Data and Validation of the Constitutive Law

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Bin Shi ◽  
Helmi Attia ◽  
Nejah Tounsi
Keyword(s):  
Shear Zone ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Orthogonal Cutting ◽  
Material Behavior ◽  
Constitutive Law ◽  
Primary Zone ◽  
Wide Range ◽  
Static Conditions ◽  
Secondary Shear Zone

This paper presents an integral methodology to obtain a wide range of constitutive data required for the identification of the constitutive equation used in simulating cutting processes. This methodology is based on combining the distributed primary zone deformation (DPZD) model developed in Part I (Shi et al., 2010, ASME J. Manuf. Sci. Eng., 132, p. 051008.) of this study with quasi-static indentation (QSI) tests, orthogonal cutting tests at room temperature (RT) and high temperature. The QSI tests are used to capture the material properties in the quasi-static conditions, which solve the unstable solutions for the coefficients of the constitutive law. The RT cutting tests are designed to fulfill the assumptions embedded in the developed DPZD model in order to provide the distributed constitutive data encountered in the primary shear zone. To capture the material behavior in the secondary shear zone, the orthogonal cutting tests with a laser preheating system are designed to raise the temperature in the primary zone to the level encountered in the secondary zone. As an application of the generated constitutive data, the Johnson–Cook model is identified for Inconel 718. This constitutive law is further validated using high speed split Hopkinson pressure bar tests and orthogonal cutting tests combined with finite element simulations. In comparison with the previous approaches reported in the open literature, the developed DPZD model and methodology significantly improve the accuracy of the simulation results.

Effect of Minimum Quantity Lubrication to Prediction of Cutting Temperature Distribution in Turning Material AISI-1045

2020 ◽  
Vol 902 ◽  
pp. 97-102
Author(s):  
Tran Trong Quyet ◽  
Pham Tuan Nghia ◽  
Nguyen Thanh Toan ◽  
Tran Duc Trong ◽  
Luong Hong Sam ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Shear Zone ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Chip Thickness ◽  
Minimum Quantity Lubrication ◽  
Minimum Quantity ◽  
The Difference ◽  
Secondary Shear Zone ◽  
Cutting Model

This paper presents a prediction of cutting temperature in turning process, using a continuous cutting model of Johnson-Cook (J-C). An method to predict the temperature distribution in orthogonal cutting is based on the constituent model of various material and the mechanics of their cutting process. In this method, the average temperature at the primary shear zone (PSZ) and the secondary shear zone (SSZ) were determined for various materials, based on a constitutive model and a chip-formation model using measurements of cutting force and chip thicknes. The J-C model constants were taken from Hopkinson pressure bar tests. Cutting conditions, cutting forces and chip thickness were used to predict shear stress. Experimental cutting heat results with the same cutting parameters using the minimum lubrication method (MQL) were recorded through the Testo-871 thermal camera. The thermal distribution results between the two methods has a difference in value, as well as distribution. From the difference, we have analyzed some of the causes, finding the effect of the minimum quantity lubrication parameters on the difference.

Investigation of Surface Characteristics and Chip Morphology in High Speed Cutting of Inconel718 Based on SHPB System

2019 ◽  
Author(s):  
Zengqiang Wang ◽  
Zhanfei Zhang ◽  
Wenhu Wang ◽  
Ruisong Jiang ◽  
Kunyang Lin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Surface Profile ◽  
Chip Morphology ◽  
Depth Of Cut ◽  
Machined Surface ◽  
High Speed Cutting

Abstract High speed cutting (HSC) technology has the characteristics of high material removal rates and high machining precision. In order to study the relationships between chip morphology and machining surface characteristic in high speed cutting of superalloy Inconel718. High-speed orthogonal cutting experiment are carried out by used a high speed cutting device based on split Hopkinson pressure bar (SHPB). The specimen surfaces and collected chips were then detected with optical microscope, scanning electron microscope and three-dimensional surface profile measuring instrument. The results show that within the experimental parameters (cutting speed from 8–16m/s, depth of cut 0.1–0.5mm), the obtained chips are sawtooth chips and periodic micro-ripple appear on the machined surface. With the cutting speed increases, machining surface roughness is decreases from 1.4 to 0.99μm, and the amplitude of periodic ripples also decreases. With the cutting depth increases, the machining surface roughness increases from 0.96 to 5.12μm and surface topography becomes worse. With the increase of cutting speed and depth of cut, the chips are transform from continues sawtooth to sawtooth fragment. By comparing the frequency of surface ripples and sawtooth chips, it is found that they are highly consistent.

Primary Chip Formation During an Extremely High Speed Micromachining Process

2004 ◽  
Author(s):  
M. J. Jackson ◽  
C. H. Hamme ◽  
L. J. Hyde ◽  
G. M. Robinson ◽  
H. Sein ◽  
...  
Keyword(s):  
Shear Zone ◽  
Chip Formation ◽  
High Speed ◽  
Cutting Tools ◽  
Machining Processes ◽  
Orthogonal Machining ◽  
Shear Process ◽  
Order Of Magnitude ◽  
Cutting Zone ◽  
Secondary Shear Zone

The advent of nanotechnology has created a demand for precision-machined substrates so that ‘bottom-up’ nanomanufacturing processes can be used to produce functional products at the nanoscale. However, machining processes must be scaled down by an order of magnitude that requires very stable desktop machine tools to produce precision-machined substrates using cutting tools that are rotated at speeds in excess of one million revolutions per minute. Therefore, the mechanics of chip formation at this scale are critical when one considers the effect of chip formation on the generation of surface roughness on the substrate. The tight curl of a machined chip in orthogonal machining appears to be part of the primary shear process. It is also known that transient tight curl occurs before a secondary shear zone develops ahead of the removal of the chip from the cutting zone. However, continuum models predict that curled chips incorporate stresses due to the establishment of a secondary shear zone. A model is presented in terms of the heterogeneous aspects of continuous chip formation, which shows very good agreement with experimental data.

scholarly journals An Instrumented High-Speed Rotor With Embedded Telemetry for the Continuous Spatial Pressure Profile Measurement in Gas Lubricated Bearings: A Proof of Concept

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Karim Shalash ◽  
Jürg Schiffmann
Keyword(s):  
System Identification ◽  
High Speed ◽  
Pressure Field ◽  
Pressure Profile ◽  
Journal Bearings ◽  
Profile Measurement ◽  
Pressure Measurements ◽  
Wide Range ◽  
Static Conditions

Abstract Pressure is the constitutive quantity governing the flow field in gas lubricated bearings. Knowledge of the pressure is of principal importance in the fundamental understanding of such bearings as well as for the validation of their models. Pressure measurements can be done from the bearing side using pressure taps, yet, several details will not be captured. In order to acquire a continuous scan of the pressure field inside the bearing, it is necessary to measure from the rotor side. This paper presents an instrumented measurement high-speed rotor with embedded pressure probes and a wireless telemetry that is capable of the continuous pressure field measurement within the gas film of journal bearings. The rotor was tested on externally pressurized gas journal bearings (EPGJBs) (D = 40 mm and L/D = 1), and pressure profile measurements were acquired up to 37.5 krpm (DN 1.5 M). Measurements at discrete points using pressure taps inside the test bearing were also performed for comparison. The measurements from both sides (bearing and rotor) were in good agreement at quasi-static conditions. At higher operational speeds, it was necessary to perform an in situ system identification and calibration for the embedded pressure probes using the bearing side measurements as a reference. The in situ system identification technique was successful to reconstruct the attenuated pressure signals for a wide range of supply pressures (amplitudes) and rotor speeds (excitation frequencies). The instrumented rotor was proven qualified to perform time-resolved pressure measurements within the gas film of journal bearings up to 37.5 krpm.

A Constitutive Law for Mitral Valve Tissue

1998 ◽  
Vol 120 (1) ◽  
pp. 38-47 ◽  
Author(s):  
K. May-Newman ◽  
F. C. P. Yin
Keyword(s):  
Mitral Valve ◽  
Transversely Isotropic ◽  
Quantitative Information ◽  
Substantial Improvement ◽  
Material Behavior ◽  
Constitutive Law ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Mechanical Models ◽  
Biaxial Mechanical Testing

Biaxial mechanical testing and theoretical continuum mechanics analysis are employed to formulate a constitutive law for cardiac mitral valve anterior and posterior leaflets. A strain energy description is formulated based on the fibrous architecture of the tissue, accurately describing the large deformation, highly nonlinear transversely isotropic material behavior. The results show that a simple three-coefficient exponential constitutive law provides an accurate prediction of stress–stretch behavior over a wide range of deformations. Regional heterogeneity may be accommodated by spatially varying a single coefficient and incorporating collagen fiber angle. The application of this quantitative information to mechanical models and bioprosthetic development could provide substantial improvement in the evaluation and treatment of valvular disease, surgery, and replacement.

scholarly journals Dynamic Recrystallization Observed at the Tool/Chip Interface in Machining

2015 ◽  
Vol 651-653 ◽  
pp. 1223-1228
Author(s):  
Yannick Senecaut ◽  
Michel Watremez ◽  
Julien Brocail ◽  
Laurence Fouilland-Paillé ◽  
Laurent Dubar
Keyword(s):  
Finite Element ◽  
Dynamic Recrystallization ◽  
Finite Element Model ◽  
Rheological Behavior ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Element Model ◽  
Numerical Results ◽  
Constitutive Law ◽  
Rheological Models

In numerical approaches for high speed machining, the rheological behavior of machined materials is usually described by a Johnson Cook law. However, studies have shown that dynamic recrystallization phenomena appear during machining in the tool/chip interface. The Johnson Cook constitutive law does not include such phenomena. Thus, specific rheological models based on metallurgy are introduced to consider these dynamic recrystallization phenomena. Two empirical models proposed by Kim et al. (2003) and Lurdos (2008) are investigated in machining modeling. A two-dimensional finite element model of orthogonal cutting, using an Arbitrary Lagrangian-Eulerian (ALE) formulation, is developed with the Abaqus/explicit software. Specific rheological models are implemented in the calculation code thanks to a subroutine. This finite element model can then predict chip formation, interfacial temperatures, chip-tool contact length, cutting forces and chip thickness with also and especially the recrystallized area. New specific experiments on an orthogonal cutting test bench are conducted on AISI 1045 steel specimens with an uncoated carbide tool. Many tests are performed and results are focused on total chip thicknesses and recrystallized chip thicknesses. Finally, compared to numerical results got with a Johnson Cook law, numerical results obtained using specific rheological models to take into account dynamic recrystallization phenomena are very close to experimental results. This work shows also the influence of rheological behavior laws on predicted results in the modeling of high speed modeling.

Predictive Analytical and Thermal Modeling of Orthogonal Cutting Process—Part I: Predictions of Tool Forces, Stresses, and Temperature Distributions

2005 ◽  
Vol 128 (2) ◽  
pp. 435-444 ◽  
Author(s):  
Yiğit Karpat ◽  
Tuğrul Özel
Keyword(s):  
Shear Zone ◽  
Thermal Modeling ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Field Analysis ◽  
Normal Stress Distribution ◽  
Modeling Approach ◽  
Temperature Distributions ◽  
Secondary Shear Zone ◽  
1045 Steel

In this paper, a predictive thermal and analytical modeling approach for orthogonal cutting process is introduced to conveniently calculate forces, stress, and temperature distributions. The modeling approach is based on the work material constitutive model, which depends on strain, strain rate, and temperature. In thermal modeling, oblique moving band heat source theory is utilized and analytically combined with modified Oxley’s parallel shear zone theory. Normal stress distribution on the tool rake face is modeled as nonuniform with a power-law relationship. Hence, nonuniform heat intensity at the tool-chip interface is obtained from the predicted stress distributions utilizing slip line field analysis of the modified secondary shear zone. Heat sources from shearing in the primary zone and friction at the tool-chip interface are combined, heat partition ratios are determined for temperature equilibrium to obtain temperature distributions depending on cutting conditions. Model validation is performed by comparing some experimental results with the predictions for machining of AISI 1045 steel, AL 6082-T6, and AL 6061-T6 aluminum. Close agreements with the experiments are observed. A set of detailed, analytically computed stress and temperature distributions is presented.

scholarly journals High-Speed Cutting of Synthetic Trabecular Bone– A Combined Experimental-Computational Investigation

2021 ◽  
Author(s):  
Macdarragh O'Neill ◽  
Ted J Vaughan
Keyword(s):  
Trabecular Bone ◽  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Computational Modelling ◽  
Isotropic Hardening ◽  
Test Machine ◽  
Modelling Framework ◽  
Wide Range

Orthopaedic surgical cutting instruments are required to generate sufficient forces to penetrate bone tissue, while minimizing the risk of thermal and mechanical damage to the surrounding environment. This study presents a combined experimental-computational approach to deter-mine relationships between key cutting parameters and overall cutting performance of a polyu-rethane-based synthetic trabecular bone analogue under orthogonal cutting conditions. An ex-perimental model of orthogonal cutting was developed, whereby an adaptable cutting tool fix-ture driven by a servo-hydraulic uniaxial test machine was used to carry out cutting tests on Sawbone® trabecular bone analogues. A computational model of the orthogonal cutting process was developed using Abaqus/Explicit, whereby an Isotropic Hardening Crushable Foam elas-tic-plastic model was used to capture the complex post-yield behaviour of the synthetic trabecu-lar bone. It was found that lower tool rake-angles resulted in the formation of larger discontin-uous chips and higher cutting forces, while higher rake angles tended to lead to more continu-ous chip formation and lower cutting forces. The computational modelling framework provided excellent predictions of both chip formation and axial cutting forces over the wide range of cut-ting parameters, when compared to experimental observations. This represents the first experi-mentally-validated computational modelling framework for orthogonal cutting of trabecular bone and excellent potential to be applied to more complex three-dimensional cutting processes in the future.

scholarly journals Internal Friction and Compressive Deformation in the Primary Zone during the High-Speed Cutting of SiCp/Al Composites

2021 ◽  
Author(s):  
Xiaoxuan Lin ◽  
Wenyuan Yang ◽  
Daochun Xu ◽  
Wenbin Li ◽  
Simin Ma
Keyword(s):  
Mathematical Model ◽  
Friction Coefficient ◽  
Internal Friction ◽  
High Speed ◽  
Compressive Strain ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Compressive Deformation ◽  
Primary Zone ◽  
Internal Friction Coefficient

Abstract The present work proposes that there is internal friction and compressive deformation in the primary zone. Mathematical model was established, in which the internal friction coefficient and some compressive characteristics of serrated chips were calculated. High-speed orthogonal cutting experiment was performed on SiCp/Al composites at cutting speeds of 10–350 m/min and feed rates of 0.07–0.12 mm/r. The internal friction and compressive deformation in the primary zone were investigated by combing results obtained in the experiments with the mathematical model. The internal friction coefficient (0.21–0.47), compressive stress (185.4 MPa–226.9 MPa), and compressive strain rate (0.013×104 /s–0.554×104 /s) increased with increasing cutting speed. However, the compression value (17.3 µm–50.0 µm) and compressive strain (0.18–0.26) decreased with the cutting speed.

Use of Electrothermal Explosion and Electro-Thermal Analyser (ETA-100) for the Study the Kinetics of Fast High-Temperature Reactions in SHS-Ceramic Systems

2010 ◽  
Vol 63 ◽  
pp. 203-212
Author(s):  
A.S. Shteinberg ◽  
A.A. Berlin
Keyword(s):  
High Temperature ◽  
Rate Constants ◽  
High Speed ◽  
Dissimilar Materials ◽  
Isothermal Kinetics ◽  
Hard Alloys ◽  
Wide Range ◽  
Static Conditions ◽  
The Impact ◽  
Kinetics Of

Due to the lack of specialty kinetic methods and instruments, the kinetics of fast hightemperature reactions SHS-ceramic systems has not been adequately studied. Recently, we have developed a number of methods of so-called non-isothermal kinetics (NIK) and designed instruments allowing one to obtain information about reactions of ceramic systems in a wide range of practically important temperatures and rates. The use of one of the NIK-methods (called electrothermal analysis based on the phenomena of electro thermal explosion) allows one to study kinetics of SHS of some ceramic materials characterized by the total reaction time ~ 10 μs. In ETE, both samples pressed from reagents powders or cylindrical samples made from tightly rolled foils were studied. The joule heating was accompanied by high-speed scanning of the non-stationary temperature field on its surface. Description and technical characteristics of the specialty device electrothermoanalyzer ETA-100 manufactured by ALOFT are given. Kinetic parameters of fast EM reactions for the temperatures up to 3600 K can be measured by ETE method using ETA-100. New kinetic data for fast high-temperature gasless SHS yielding individual and composite materials (including refractory carbides and borides of transition metals, silicon and boron carbides, some refractory oxides and hard alloys) are presented. At high-speed impact of the samples, the reaction rate constants were found to exceed the combustion rate constants (measured by ETA-100) by many orders of magnitude. It was concluded that the kinetic mechanisms of the corresponding fast reactions in the static conditions and under the impact are dramatically different. It was shown that SHS in ETE mode has a significant potential as a modern practical method to be used for welding of refractory and dissimilar materials, production of coarse superabrasives, etc.

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