A Finite Element Study of Chip Formation Process in Orthogonal Machining

2012 ◽  
pp. 197-225
Author(s):  
Amrita Priyadarshini ◽  
Surjya K. Pal ◽  
Arun K. Samantaray
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
Critical Role ◽  
Fe Model ◽  
Orthogonal Machining ◽  
Adiabatic Shearing ◽  
Segmented Chip ◽  
The Right ◽  
Distribution Of Stress ◽  
Continuous Chip

This paper examines the plane strain 2D Finite Element (FE) modeling of segmented, as well as continuous chip formation while machining AISI 4340 with a negative rake carbide tool. The main objective is to simulate both the continuous and segmented chips from the same FE model based on FE code ABAQUS/Explicit. Both the adiabatic and coupled temperature displacement analysis has been performed to simulate the right kind of chip formation. It is observed that adiabatic hypothesis plays a critical role in the simulation of segmented chip formation based on adiabatic shearing. The numerical results dealing with distribution of stress, strain and temperature for segmented and continuous chip formations were compared and found to vary considerably from each other. The simulation results were also compared with other published results; thus validating the developed model.

A Finite Element Study of Chip Formation Process in Orthogonal Machining

2011 ◽  
Vol 1 (4) ◽  
pp. 19-45 ◽  
Author(s):  
Amrita Priyadarshini ◽  
Surjya K. Pal ◽  
Arun K. Samantaray
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
Critical Role ◽  
Fe Model ◽  
Orthogonal Machining ◽  
Adiabatic Shearing ◽  
Segmented Chip ◽  
The Right ◽  
Distribution Of Stress ◽  
Continuous Chip

This paper examines the plane strain 2D Finite Element (FE) modeling of segmented, as well as continuous chip formation while machining AISI 4340 with a negative rake carbide tool. The main objective is to simulate both the continuous and segmented chips from the same FE model based on FE code ABAQUS/Explicit. Both the adiabatic and coupled temperature displacement analysis has been performed to simulate the right kind of chip formation. It is observed that adiabatic hypothesis plays a critical role in the simulation of segmented chip formation based on adiabatic shearing. The numerical results dealing with distribution of stress, strain and temperature for segmented and continuous chip formations were compared and found to vary considerably from each other. The simulation results were also compared with other published results; thus validating the developed model.

Evidence of thermoplastic instability about segmented chip formation process for Ti–6Al–4V alloy based on the finite-element method

2011 ◽  
Vol 225 (6) ◽  
pp. 1407-1417 ◽  
Author(s):  
G Chen ◽  
C Ren ◽  
X Yang ◽  
T Guo
Keyword(s):  
Finite Element ◽  
Formation Mechanism ◽  
Failure Criterion ◽  
Formation Process ◽  
Chip Formation ◽  
Deformation Zone ◽  
Chip Morphology ◽  
Fe Model ◽  
Friction Characteristic ◽  
Segmented Chip

A ductile failure law and an energy-based failure criterion have been implemented in a 2D finite-element (FE) model to simulate the segmented chip formation process in titanium alloy (Ti–6Al–4V) machining. The variations of stress and strain are taken into account in defining the material failure criterion. The cutting forces and chip morphology calculated by FE model are compared with experimental results in good agreement, validating the FE model. Stresses, strains, cutting temperatures, and stiffness degradation along adiabatic shear bands (ASBs) are analysed during the segment formation process to investigate the segment formation mechanism. It is found that the variation trend of strains is the same as that of temperatures, in addition, the variation of strains and their changing-rate lag slightly behind those of temperatures. These observations provide a new evidence of thermoplastic instability along ASB and increase the understanding of segmented chip formation mechanism. Furthermore, simulation results show that ASB morphology and its forming mechanism are mainly caused by thermoplastic instability in primary deformation zone and friction characteristic in the second deformation zone.

3D Finite Element Analysis for the High Speed Machining of Hardened Steel

Manufacturing ◽  
2002 ◽  
Author(s):  
Eu-gene Ng ◽  
Tahany I. El-Wardany ◽  
Mihaela Dumitrescu ◽  
Mohamed A. Elbestawi
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
High Speed ◽  
Chip Thickness ◽  
Element Model ◽  
High Speed Machining ◽  
Element Analysis ◽  
Segmented Chip ◽  
The Right ◽  
Cutting Speeds

The objective of this research is to illustrate the importance of modeling the right/similar chip formation with experimental results. When machining ‘difficult to cut’ materials at high cutting speeds, segmented chips are usually formed. When modeling the cutting process, it is important to consider the type of chip formed, as this affects the stress field generated in the workpiece. The modeled chips have to be the same type as those obtained during experimental work. However very few published models were capable of modeling the 3D oblique cutting with segmented chip formation. This paper presents a finite element model that includes a user customized catastrophic slip criterion and crack propagation module to model segmented chip formation in orthogonal & oblique machining of hardened AISI 4340 steel (52±2 HRC). Predicted cutting forces and chip thickness for segmented chips were in close agreement with experimental data. The modeled plastic strain and temperature distribution/magnitude were very different for continuous and segmented chip formation.

scholarly journals A Novel Rat Model of Orthodontic Tooth Movement Using Temporary Skeletal Anchorage Devices: 3D Finite Element Analysis andIn VivoValidation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Neelambar Kaipatur ◽  
Yuchin Wu ◽  
Samer Adeeb ◽  
Thomas Stevenson ◽  
Paul Major ◽  
...  
Keyword(s):  
Finite Element ◽  
Alveolar Bone ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Von Mises Stress ◽  
Fe Model ◽  
Sprague Dawley ◽  
Element Analysis ◽  
Von Mises ◽  
The Right

The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built usingμCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. Forin vivovalidation of the FE model, Sprague-Dawley rats (n=25) were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs.

Investigation on Chip Formation during Machining Using Finite Element Modeling

2012 ◽  
Vol 505 ◽  
pp. 31-36 ◽  
Author(s):  
Moaz H. Ali ◽  
Basim A. Khidhir ◽  
Bashir Mohamed ◽  
A.A. Oshkour
Keyword(s):  
Finite Element ◽  
Tool Wear ◽  
Finite Element Modeling ◽  
Chip Formation ◽  
Cutting Tool ◽  
Chip Morphology ◽  
Machining Process ◽  
Element Modeling ◽  
Segmented Chip ◽  
Cutting Speeds

Titanium alloys are desirable materials for aerospace industry because of their excellent combination of high specific strength, lightweight, fracture resistant characteristics, and general corrosion resistance. Therefore, the chip morphology is very important in the study of machinability of metals as well as the study of cutting tool wear. The chips are generally classified into four groups: continuous chips, chips with built-up-edges (BUE), discontinuous chips and serrated chips. . The chip morphology and segmentation play a predominant role in determining machinability and tool wear during the machining process. The mechanics of segmented chip formation during orthogonal cutting of titanium alloy Ti–6Al–4V are studied in detail with the aid of high-speed imaging of the chip formation zone. The finite element model of chip formation of Ti–6Al–4V is suggested as a discontinuous type chip at lower cutting speeds developing into a continuous, but segmented, chip at higher cutting speeds. The prediction by using finite-element modeling method and simulation process in machining while create chips formation can contribute in reducing the cost of manufacturing in terms of prolongs the cutting tool life and machining time saving.

Finite element analysis of intramedullary devices: The effect of the gap between the implant and the bone

2008 ◽  
Vol 222 (3) ◽  
pp. 333-345 ◽  
Author(s):  
D J Simpson ◽  
C J Brown ◽  
A L Yettram ◽  
P Procter ◽  
G J Andrew
Keyword(s):  
Finite Element ◽  
Fracture Plane ◽  
Local Geometry ◽  
Fe Model ◽  
Fe Modelling ◽  
Element Analysis ◽  
Medial Side ◽  
Intramedullary Device ◽  
Interaction Interface ◽  
Distribution Of Stress

This paper examines the interaction interface between the implant and the bone for an intramedullary femoral nailing system using a finite element (FE) model and specifically considers the hypothesis that the local geometry at the interface is significant to the resulting localized contact stress between the medial and lateral aspect of nail and endosteum. Contact mechanics algorithms are used in the FE modelling technique that can be developed to deal with any form of intramedullary device for which contact at the bone—implant interface is important. Global stiffness data from the FE model are compared with available data from an experiment carried out on a construct of the bone and the device that uses intramedullary femoral nails. Acceptable agreement is obtained. The results demonstrate that the mechanical interface between the implant and the bone is significantly affected by the gap geometry and magnitude. In particular, larger gaps lead to greater concentrations of stress on the medial side, while the distribution of stress is more uniform at the lateral contacts. Furthermore, the results show that the gap can have a marked effect on the stresses that occur on the fracture plane.

Experimental Evaluation and Modeling Analysis of Micromilling of Hardened H13 Tool Steels

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Hongtao Ding ◽  
Ninggang Shen ◽  
Yung C. Shin
Keyword(s):  
Tool Wear ◽  
Size Effect ◽  
Strain Gradient ◽  
Chip Formation ◽  
Experimental Evaluation ◽  
Strain Gradient Plasticity ◽  
Fe Model ◽  
Tool Steels ◽  
Gradient Plasticity ◽  
Continuous Chip

This study is focused on experimental evaluation and numerical modeling of micromilling of hardened H13 tool steels. Multiple tool wear tests are performed in a microside cutting condition with 100 μm diameter endmills. The machined surface integrity, part dimension control, size effect, and tool wear progression in micromachining of hardened tool steels are experimentally investigated. A strain gradient plasticity model is developed for micromachining of hardened H13 tool steel. Novel 2D finite element (FE) models are developed in software ABAQUS to simulate the continuous chip formation with varying chip thickness in complete micromilling cycles under two configurations: microslotting and microside cutting. The steady-state cutting temperature is investigated by a heat transfer analysis of multi micromilling cycles. The FE model with the material strain gradient plasticity is validated by comparing the model predictions of the specific cutting forces with the measured data. The FE model results are discussed in chip formation, stress, temperature, and velocity fields to great details. It is shown that the developed FE model is capable of modeling a continuous chip formation in a complete micromilling cycle, including the size effect. It is also shown that the built-up edge in micromachining can be predicted with the FE model.

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