Computational Machining of Titanium Alloy—Finite Element Modeling and a Few Results

1996 ◽  
Vol 118 (2) ◽  
pp. 208-215 ◽  
Author(s):  
T. Obikawa ◽  
E. Usui
Keyword(s):  
Finite Element ◽  
Titanium Alloy ◽  
Finite Elements ◽  
Finite Element Modeling ◽  
Metal Cutting ◽  
Shape Change ◽  
Geometrical Nonlinearity ◽  
Deformation Analysis ◽  
Element Modeling ◽  
Serrated Chips

A Finite element modeling was developed for the computational machining of titanium alloy Ti-6Al-4V. The chip formation in metal cutting is one of the large deformation problems, thus, in the formulation of the elastic-plastic deformation analysis, geometrical nonlinearity due to the large shape change of the finite elements was taken into account and the over-constraint of incompressibility on the deformation of ordinary finite elements in the plastic range was relaxed to make the elements deformable as a real continuum. A ductile fracture criterion on the basis of strain, strain rate, hydrostatic pressure and temperature was applied to the crack growth during the chip segmentation. The temperature field in the flowing chip and workpiece and the fixed tool was calculated simultaneously by an unsteady state thermal conduction analysis and the remeshing of tool elements. The serrated chips predicted by the computational machining showed striking resemblances in the shape and irregular pitch of those obtained by actual cutting. The mean cutting forces and the amplitude of cutting force vibration in the computational machining were in good agreement with those in the actual machining.

scholarly journals Finite Element Modeling and Simulation of Machining of Titanium Alloy and H13 Tool Steel Using PCBN Tool

2013 ◽  
Vol 392 ◽  
pp. 36-40 ◽  
Author(s):  
S. Sulaiman ◽  
A. Roshan ◽  
S. Borazjani
Keyword(s):  
Finite Element ◽  
Titanium Alloy ◽  
High Temperature ◽  
Stress Distribution ◽  
Finite Element Modeling ◽  
Tool Steel ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Tool Material ◽  
Element Modeling

This paper deals with finite element modeling (FEM) and simulation of machining of titanium alloy and H-13 tool steel. Titanium alloys are very suitable for airframe manufacture and aircraft as H-13 uses forging dies and machined die casting. The machinability of both metals was evaluated by high temperature and tool wear. Finite element simulation was performed with ABAQUS explicit software to predict cutting temperature and stress distribution during metal cutting process. The purpose of this study was evaluation the performance of PCBN cutting tool material on machining of titanium alloy and H-13. It was found that PCBN tool can resistant well against high thermal shocks, high temperature and stress distribution when machining difficult to cut materials. The results can give a better understanding of cutting tool material for metal cutting process.

A Comparative Evaluation of Finite Element Modeling of Creep Deformation of Fuel Channels in CANDU® Nuclear Reactors

2018 ◽  
Author(s):  
F. J. Tallavo ◽  
M. D. Pandey ◽  
M. Jyrkama ◽  
N. C. Christodoulou ◽  
G. A. Bickel ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Creep Deformation ◽  
Nuclear Reactors ◽  
Deformation Analysis ◽  
Control Mechanisms ◽  
3D Fem ◽  
Fem Model ◽  
Fuel Channel ◽  
Element Modeling

A key element of the fuel channel life cycle management in CANDU® nuclear reactors is to prevent contact between the pressure tube (PT) and the calandria tube (CT) in a fuel channel. By preventing PT-CT contact, the development of hydride blisters and delayed hydride cracking of the PT can be avoided. The PT-CT contact is a result of in-reactor deformation due to irradiation induced creep of the fuel channel assembly. Excessive sagging of the PT can also interfere with the free passage of the fuel bundles when the channel is refueled. Contact of the CT with reactor control mechanisms located horizontally between the fuel channels can result from excessive sag of the CT. The prediction of dimensional changes due to in-reactor creep and the time of PT-CT contact is calculated using finite element modeling of the fuel channel with appropriate creep constitutive laws describing PT and CT deformation. The three-dimensional nature of creep deformation of fuel channels can be approximated by a one-dimensional finite element model (1D-FEM), which is a computationally tractable problem. However, the simplifications of a 1D-FEM model come at the expense of loss of prediction accuracy. This paper compares creep deformation analysis of fuel channels using 1D-FEM and 3D-FEM models. The comparison is based on PT and CT sag profiles as well as on PT-CT gap at different time intervals during service of the fuel channel. Results from the comparative analysis show that the 1D-FEM model predicts greater values of PT-CT gap. The difference in gap predicted between both FEM models increases rapidly when the minimum gap is located in the outlet span. At 250,000 equivalent full power hours, the 1D-FEM model overestimate the gap by 1.12 mm with respect to the 3D-FEM model.

Finite Element Modeling of Chip Formation in the Domain of Negative Rake Angle Cutting

2003 ◽  
Vol 125 (3) ◽  
pp. 324-332 ◽  
Author(s):  
Y. Ohbuchi ◽  
T. Obikawa
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Undeformed Chip Thickness ◽  
Element Modeling ◽  
Single Grain ◽  
Serrated Chips

A thermo-elastic-plastic finite element modeling of orthogonal cutting with a large negative rake angle has been developed to understand the mechanism and thermal aspects of grinding. A stagnant chip material ahead of the tool tip, which is always observed with large negative rake angles, is assumed to act like a stable built-up edge. Serrated chips, one of typical shapes of chips observed in single grain grinding experiment, form when analyzing the machining of 0.93%C carbon steel SK-5 with a rake angle of minus forty five or minus sixty degrees. There appear high and low temperature zones alternately according to severe and mild shear in the primary shear zone respectively. The shapes of chips depend strongly on the cutting speed and undeformed chip thickness; as the cutting speed or the undeformed chip thickness decreases, chip shape changes from a serrated type to a bulging one to a wavy or flow type. Therefore, there exists the critical cutting speed over which a chip can form and flow along a rake face for a given large negative rake angle and undeformed chip thickness.

Simulation machining of titanium alloy (Ti-6Al-4V) based on the finite element modeling

2013 ◽  
Vol 36 (2) ◽  
pp. 315-324 ◽  
Author(s):  
Moaz H. Ali ◽  
M. N. M. Ansari ◽  
Basim A. Khidhir ◽  
Bashir Mohamed ◽  
A. A. Oshkour
Keyword(s):  
Finite Element ◽  
Titanium Alloy ◽  
Finite Element Modeling ◽  
Element Modeling
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