Prediction of Chip Morphology and Cutting Force during Prestressed Cutting of TC4

2013 ◽  
Vol 288 ◽  
pp. 318-322
Author(s):  
Rui Tao Peng ◽  
Jia Yi Wu ◽  
Xin Zi Tang ◽  
Yuan Qiang Tan
Keyword(s):  
Stress Distribution ◽  
Cutting Force ◽  
Chip Formation ◽  
Subsurface Layer ◽  
Chip Morphology ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Forming Process ◽  
Energy Effect ◽  
Force Curves

Chip morphology plays a predominant role in determining machinability and tool wear during the machining of titanium alloys. Chip formation process in prestressed cutting of titanium alloy TC4 was numerically explored via the finite element method. Crack initiation during the chip segmentation was realized by using a ductile fracture criterion which based on the strain energy. Effect of prestress on cutting force and chip formation as well as Mises stress distributions were revealed. The results indicate that chips show the similar characteristic of continuous and regular serrated shape, which is not affected by prestress. Initial stress distribution of workpiece was changed by prestress, which correspondingly leads to the alteration of stress distribution in the subsurface layer. The generated cutting force curves share the same average amplitude and analogous rhythm, which correspond to the chip forming process respectively.

Evaluation of Stress Shielding for Three Types of Implanted Femurs Based on Stress Distribution

2013 ◽  
Vol 459 ◽  
pp. 524-529
Author(s):  
Koki Ouchi ◽  
Gang Deng ◽  
Go Yamako ◽  
Etsuo Chosa ◽  
Tsutomu Nakanishi
Keyword(s):  
Total Hip Arthroplasty ◽  
Stress Distribution ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Gruen Zone ◽  
Total Hip ◽  
Method Analysis ◽  
Thrust Plate Prosthesis

This research investigates the stress distribution of the three types of implanted femurs using the finite element method analysis. The comparisons of the stress distribution between the implanted femursand the healthy femur were performed and the characteristics in the stress shielding of each casewere clarified. Since the load is transferred on the contact surface between the implant and the inner surface of the femur in the case of the total hip arthroplasty, the stress in the intertrochanteric zone (Gruen zone 7) become very small, and the phenomenon of the stress shielding is confirmed obviously. The stress distributions of the femurs afterthe resurfacing hiparthroplasty and the thrust plate prosthesis are about the same with that of the healthy femur, so, the possibility of the stress shielding is considered lower compared with the femur after the total hip arthroplasty. However, considering the stress concentration thatwill increase the risk of femoral fracture caused by the screws for the fixation of the implant in the thrust plate prosthesis, the resurfacing hiparthroplastymay beconcluded as the best method among these three types of implants to avoid stress shielding.

Analytical Prediction of Three Dimensional Cutting Process—Part 1: Basic Cutting Model and Energy Approach

1978 ◽  
Vol 100 (2) ◽  
pp. 222-228 ◽  
Author(s):  
E. Usui ◽  
A. Hirota ◽  
M. Masuko
Keyword(s):  
Cutting Force ◽  
Chip Formation ◽  
Single Point ◽  
Orthogonal Cutting ◽  
Three Dimensional ◽  
Analytical Prediction ◽  
Forming Process ◽  
Proposed Model ◽  
Edge Based ◽  
Cutting Model

The paper proposes a new model of chip forming process in three dimensional cutting with single point tool, in which the process is interpreted as a piling up of orthogonal cuttings along the cutting edge. Based upon the proposed model, an energy method similar to the upper bound approach, which enables to predict the chip formation and the three components of cutting force by using only the orthogonal cutting data, is developed. The method is also applied to predict chip formation and cutting force in oblique cutting, plain milling, and groove cutting operations.

The Periodical Fluctuation of Residual Stress in Hard Turned Surface and its Relationship With Chip Formation

2011 ◽  
Author(s):  
Xueping Zhang ◽  
Shenfeng Wu ◽  
C. Richard Liu
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Chip Formation ◽  
Chip Morphology ◽  
Residual Stress Distribution ◽  
Cutting Edge ◽  
Fluctuation Frequency ◽  
Cutting Direction ◽  
Edge Tool

To evaluate the residual stress distribution along cutting direction in hard turning process, an explicit dynamic thermo-mechanical orthogonal Finite Element Model (FEM) is developed to consider the correlation between residual stress distribution and chip morphology and plough effect by cutting edge. The FEM adopts Johnson-Cook (J-C) model to describe work material property, the critical equivalent plastic strain criterion to simulate chip separation behavior, and the revised coulomb’s law to capture the friction pattern between the tool and chip interface. The FEM is validated by comparing the predicted and experimental chip morphology and residual stress distribution. The residual stress distribution in hard machined surface along cutting direction is accurately captured by using sharp and honed cutting edge tools. The residual stresses by sharp tool demonstrate a periodical characteristic, the fluctuation amplitudes are determined in the surface and subsurface along the cutting direction, and the fluctuation frequency corresponds to that of the saw-tooth chip. However, the residual stresses by honed cutting edge tool demonstrate an indistinct periodic characteristic, the fluctuation frequency in surface and subsurface is larger than that of the saw-tooth chip. Saw-tooth chip formation process by sharp tool is identified to analyze the residual stress scatter periodic mechanism, which associates with the fluctuation of cutting force and temperature. The plough process by honed cutting edge tool is identified to explain the equilibrium effect on the amplitude and frequency of residual stress scatter in hard turned surface and subsurface. The periodical fluctuation characteristics of residual stress in hard turned surface and subsurface is revealed and verified by determining its amplitude and frequency corresponding to that of the saw-tooth chip. The analysis will enhance the fatigue life prediction accuracy by incorporating the effect of residual stresses periodical fluctuation on the crack initiation and propagation life in hard turned surface and subsurface.

Effect of Microstructure on Cutting Force and Chip Formation during Machining of Ti-6Al-4V Alloy

2013 ◽  
Vol 690-693 ◽  
pp. 2437-2441 ◽  
Author(s):  
Shou Jin Sun ◽  
Milan Brandt ◽  
John P.T. Mo
Keyword(s):  
Cutting Force ◽  
Chip Formation ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Lamellar Microstructure ◽  
Chip Morphology ◽  
Dry Machining ◽  
Segmented Chip ◽  
Different Types ◽  
Fully Lamellar

Dry machining was conducted on Ti-6Al-4V alloy with three different types of microstructure: globular, bi-modal and fully lamellar microstructures. The effects of cutting speed on the cutting force and chip formation were investigated. The differences in cutting force and chip morphology are found only at cutting speed lower than 100m/min. The main cutting force and chip thickness when machining Ti-6Al-4V alloy with globular microstructure are lower than these when cutting Ti-6Al-4V alloy with bi-modal and fully lamellar microstructures at cutting speed lower than 100m/min. The tendency of segmented chip formation is the highest for cutting Ti-6Al-4V alloy with fully lamellar microstructure and the lowest for machining Ti-6Al-4V alloy with bi-modal microstructure at cutting speed lower than 100m/min because of their differences in increase of shear strength with strain rate.

scholarly journals Concept for controlled adjustment of residual stress states in semi-finished products by gradation extrusion

2021 ◽  
Author(s):  
René Selbmann ◽  
Markus Baumann ◽  
Mateus Dobecki ◽  
Markus Bergmann ◽  
Verena Kräusel ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Experimental Tests ◽  
Residual Stress Distribution ◽  
Forming Process ◽  
Compressive Stresses ◽  
Energy Consuming ◽  
Stress States ◽  
Set Up ◽  
Time And Energy

AbstractThe residual stress distribution in extruded components and wires after a conventional forming process is frequently unfavourable for subsequent processes, such as bending operations. High tensile residual stresses typically occur near the surface of the wire and thus limit further processability of the material. Additional heat treatment operations or shot peening are often inserted to influence the residual stress distribution in the material after conventional manufacturing. This is time and energy consuming. The research presented in this paper contains an approach to influence the residual stress distribution by modifying the forming process for wire-like applications. The aim of this process is to lower the resulting tensile stress levels near the surface or even to generate compressive stresses. To achieve these residual compressive stresses, special forming elements are integrated in the dies. These modifications in the forming zone have a significant influence on process properties, such as degree of deformation and deformation direction, but typically have no influence on the diameter of the product geometry. In the present paper, the theoretical approach is described, as well as the model set-up, the FE-simulation and the results of the experimental tests. The characterization of the residual stress states in the specimen was carried out by X-ray diffraction using the sin2Ψ method.

Finite Element Analysis of Poor Distal Contact of the Femoral Component of a Cementless Hip Endoprosthesis

1993 ◽  
Vol 207 (4) ◽  
pp. 255-261 ◽  
Author(s):  
M Taylor ◽  
E W Abel
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Hip Endoprosthesis ◽  
Applied Loading ◽  
Femoral Geometry ◽  
Contact Models

The difficulty of achieving good distal contact between a cementless hip endoprosthesis and the femur is well established. This finite element study investigates the effect on the stress distribution within the femur due to varying lengths of distal gap. Three-dimensional anatomical models of two different sized femurs were generated, based upon computer tomograph scans of two cadaveric specimens. A further six models were derived from each original model, with distal gaps varying from 10 to 60 mm in length. The resulting stress distributions within these were compared to the uniform contact models. The extent to which femoral geometry was an influencing factor on the stress distribution within the bone was also studied. Lack of distal contact with the prosthesis was found not to affect the proximal stress distribution within the femur, for distal gap lengths of up to 60 mm. In the region of no distal contact, the stress within the femur was at normal physiological levels associated with the applied loading and boundary conditions. The femoral geometry was found to have little influence on the stress distribution within the cortical bone. Although localized variations were noted, both femurs exhibited the same general stress distribution pattern.

Stress Distribution Analysis of Different Types of Blade for a Fermentation System

2013 ◽  
Vol 479-480 ◽  
pp. 319-323
Author(s):  
Cheng Chi Wang ◽  
Po Jen Cheng ◽  
Kuo Chi Liu
Keyword(s):  
Stress Distribution ◽  
Maximum Stress ◽  
Effective Means ◽  
Materials Processing ◽  
Distribution Analysis ◽  
Stress Distributions ◽  
Fermentation System ◽  
Different Types ◽  
Inclined Angle ◽  
Key Parameter

Fermentation system is widely used for food manufacturing, materials processing and chemical reaction etc. Different types of blade in the tank for fermentation cause distinct stress distributions on the surface between fluid and blade, and appear various flow fields in the tank. So, this paper is mainly focused on analyzing the stress field of blades under different scales of blade with fixing rotational speed. The results show that the ratio of blade length to width influences stress distribution on the blades. At the same time, the inclined angle of blade is also the key parameter for the consideration of design and appropriate design will decrease the maximum stress. The results provide an effective means of gaining insights into the stress distribution of fermentation system.

Numerical Study of the Flow Forming Process of AISI 630 Stainless Steel

2011 ◽  
Vol 264-265 ◽  
pp. 24-29 ◽  
Author(s):  
Seyed Mohammad Ebrahimi ◽  
Seyed Ali Asghar Akbari Mousavi ◽  
Mostafa Soltan Bayazidi ◽  
Mohammad Mastoori
Keyword(s):  
Feeding Rate ◽  
Surface Defects ◽  
Numerical Study ◽  
Internal Diameter ◽  
The Finite Element Method ◽  
Forming Process ◽  
Flow Forming ◽  
Cold Forming ◽  
External Variables ◽  
Experimental Process

Flow forming is one of the cold forming process which is used for hollow symmetrical shapes. In this paper, the forward flow forming process is simulated using the finite element method and its results are compared with the experimental process. The variation of thickness of the sample is examined by the ultrasonic tests for the five locations of the tubes. To simulate the process, the ABAQUS explicit is used. The effects of flow forming variables such as the angle of rollers and rate of feeding of rollers, on the external variables such as internal diameter, thickness of tube and roller forces are considered. The study showed that the roller force and surface defects were reduced with low feeding rate and low rollers attack angles. Moreover, the sample internal diameter increased at low feeding rate and low rollers attack angles. The optimum variables for flow forming process were also obtained.

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