Identification of Material Constitutive Laws for Machining—Part I: An Analytical Model Describing the Stress, Strain, Strain Rate, and Temperature Fields in the Primary Shear Zone in Orthogonal Metal Cutting

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Bin Shi ◽  
Helmi Attia ◽  
Nejah Tounsi
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Shear Zone ◽  
Analytical Model ◽  
Metal Cutting ◽  
Effective Strain ◽  
Cutting Process ◽  
Temperature Fields ◽  
Stress Strain ◽  
Orthogonal Metal Cutting

To achieve high performance machining, modeling of the cutting process is necessary to predict cutting forces, residual stresses, tool wear, and burr formation. A major difficulty in the modeling of the cutting process is the description of the material constitutive law to reflect the severe plastic deformation encountered in the primary and the secondary deformation zones under high strains, strain rates, and temperatures. A critical literature review shows that the available methods to identify the material constitutive equation for the cutting process may lead to significant errors due to their limitations. To overcome these limitations, a novel methodology is developed in this study. Through conceptual considerations and finite element simulations, the characteristics of the stress, strain, strain rate, and temperature fields in the primary shear zone were established. Using this information and applying the principles of the theory of plasticity, heat transfer, and mechanics of the orthogonal metal cutting, a new distributed primary zone deformation model is developed to describe the distributions of the effective stress, effective strain, effective strain rate, and temperature in the primary shear zone. This analytical model is assessed by comparing its predictions with finite element simulation results under a wide range of cutting conditions using different materials. Experimental validation of this model will be presented in Part II of this study.

Finite Element Simulation of Orthogonal Metal Cutting

1995 ◽  
Vol 117 (1) ◽  
pp. 84-93 ◽  
Author(s):  
A. J. Shih
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Metal Cutting ◽  
Sliding Friction ◽  
Large Strain ◽  
Cutting Process ◽  
Shear Stresses ◽  
Friction Behavior ◽  
Element Mesh ◽  
Orthogonal Metal Cutting

The development and implementation of a plane-strain finite element method for the simulation of orthogonal metal cutting with continuous chip formation are presented. Detailed work-material modeling, including the effects of elasticity, viscoplasticity, temperature, large strain, and high strain-rate, is used to simulate the material deformation during the cutting process. The unbalanced force reduction method and sticking-sliding friction behavior are implemented to analyze the cutting process. The deformation of the finite element mesh and comparisons of residual stress distributions with X-ray diffraction measurements are presented. Simulation results along the primary and secondary deformation zones and under the cut surface, e.g., the normal and shear stresses, temperature, strain-rate, etc., are presented revealing insight into the metal cutting process.

Finite Element Simulation of the Orthogonal Metal Cutting Process

2004 ◽  
Vol 471-472 ◽  
pp. 582-586 ◽  
Author(s):  
Shi Jin Chen ◽  
Q.L. Pang ◽  
K. Cheng
Keyword(s):  
Finite Element ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Element Model ◽  
Cutting Process ◽  
Machined Surface ◽  
Cutting Test ◽  
Orthogonal Metal Cutting ◽  
Discontinuous Cutting ◽  
Cutting Processes

In this paper, a finite element model of a two-dimensional orthogonal metal cutting process is used to simulate the chip formation, cutting forces, stress, strain and temperature distributions. Two deformable parts are involved in this model: the workpiece and the cutting tool. To make the results of the simulation agree the orthogonal cutting test better, the separation surface between the chip and the machined surface is not predefined in this simulation. The chip-separation criterion is based on the Johnson and Cook law. This work will help as a reference to tackle more complex cutting processes such as oblique and discontinuous cutting.

Finite Element Modeling of Orthogonal Metal Cutting

1991 ◽  
Vol 113 (3) ◽  
pp. 253-267 ◽  
Author(s):  
K. Komvopoulos ◽  
S. A. Erpenbeck
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Metal Cutting ◽  
Finite Element Simulations ◽  
Cutting Process ◽  
Critical Parameters ◽  
Interfacial Friction ◽  
Rake Face ◽  
Workpiece Material ◽  
Orthogonal Metal Cutting

The finite element method was used to model chip formation in orthogonal metal cutting. Emphasis was given on analyzing the effect of important factors, such as plastic flow of the workpiece material, friction at the tool-workpiece interface, and wear of the tool, on the cutting process. To simulate separation of the chip from the workpiece, superposition of two nodes at each nodal location of a parting line of the initial mesh was imposed. According to the developed algorithm, the superimposed nodes were constrained to assume identical displacements, until approaching to a specified small distance from the tool tip. At that juncture, the displacement constraint was removed and separation of the nodes was allowed. Under the usual plane strain assumption, quasi-static finite element simulations of orthogonal metal cutting were performed for interfacial friction coefficients equal to zero, 0.15, and 0.5 and unworn or worn (cratered) tools having a strongly adherent built-up edge. To investigate the significance of the deformation of the workpiece material on the cutting process, elastic-perfectly plastic and elastic-plastic with isotropic strain hardening and strain rate sensitivity constitutive laws were used in the analysis. For simplicity, the tool material and the built-up edge were modeled as perfectly rigid. In all cases analyzed, the cutting speed and depth of cut were set equal to 183 m/min and 1.27 mm, respectively. Experiments confirmed that cutting of AISI 4340 steel with ceramic-coated tools under similar conditions led to the development of a built-up edge and the formation of continuous chips. The dimensions of the crater, assumed in the finite element simulations involving a cratered tool, were also determined from the same cutting experiments. Spatial distributions of the equivalent total plastic strain and the von Mises equivalent stress corresponding to steady-state cutting conditions and the normal and shear stresses at the rake face are contrasted and interpreted qualitatively in terms of critical parameters. The influence of interfacial friction, metal flow characteristics, and wear at the rake face of the tool on the steady-state magnitudes of the cutting forces, shear plane angle, chip thickness, and chip-tool contact length are also elucidated. Several aspects of the metal cutting process predicted by the finite element model agreed well with experimental results and phenomenological observations.

A Finite Element Model of Orthogonal Metal Cutting

1985 ◽  
Vol 107 (4) ◽  
pp. 349-354 ◽  
Author(s):  
J. S. Strenkowski ◽  
J. T. Carroll
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Metal Cutting ◽  
Element Model ◽  
Effective Plastic Strain ◽  
Orthogonal Metal Cutting ◽  
Chip Separation ◽  
Chip Geometry

A finite element model of orthogonal metal cutting is described. The paper introduces a new chip separation criterion based on the effective plastic strain in the workpiece. Several cutting parameters that are often neglected in simplified metal-cutting models are included, such as elastic-plastic material properties of both the workpiece and tool, friction along the tool rake face, and geometry of the cutting edge and workpiece. The model predicts chip geometry, residual stresses in the workpiece, and tool stresses and forces, without any reliance on empirical metal cutting data. The paper demonstrates that use of a chip separation criterion based on effective plastic strain is essential in predicting chip geometry and residual stresses with the finite element method.

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