A Numerical Analysis on the Dissimilar Channel Angular Pressing Process by Rolling

2005 ◽  
Vol 475-479 ◽  
pp. 3231-3234 ◽  
Author(s):  
Moo Young Huh ◽  
Hyoung Jin Choi ◽  
J.H. Ok ◽  
Beong Bok Hwang ◽  
Bok Choon Kang
Keyword(s):  
Strain State ◽  
Model Material ◽  
Radius Of Curvature ◽  
Strain Component ◽  
Large Radius ◽  
Rigid Plastic ◽  
Center Layer ◽  
Angular Pressing ◽  
Dimensional Finite Element ◽  
Deformation Mechanics

The dissimilar channel angular pressing (DCAP) process by rolling was numerically modeled and analyzed by the rigid-plastic two-dimensional finite element method in order to optimize the strain state of the DCAP process. Three distinct deformation mechanics during DCAP by rolling includes rolling, bending, and shearing. AA 1100 aluminum alloy was selected as a model material for the analysis of DCAP process. Difference in the friction conditions between the upper and lower roll surfaces led to large variation of shear strain component throughout the thickness of sample. Strain accompanying bending turned out to be negligible because of a large radius of curvature by relatively large roll diameter. The concentrated shear deformation was monitored at the corner of the DCAP-channel where the abrupt change in the direction of material flow occurred. The strain state at the upper and lower surfaces was observed to vary strongly from that of the center layer of the sheet.

Numerical Analysis on the Dissimilar Channel Angular Pressing by Multi-Pass Rolling

2004 ◽  
Vol 449-452 ◽  
pp. 101-104 ◽  
Author(s):  
Hyoung Jin Choi ◽  
Beong Bok Hwang ◽  
B.D. Ko ◽  
Joong Yeon Lim ◽  
D.H. Jang
Keyword(s):  
Shear Deformation ◽  
Material Flow ◽  
Abrupt Change ◽  
Effective Strain ◽  
Strain History ◽  
Two Dimensional ◽  
Rigid Plastic ◽  
Angular Pressing ◽  
Strain Components ◽  
Dimensional Finite Element

The dissimilar channel angular pressing (DCAP or CCSS) based on the equal channel angular pressing (ECAP) was numerically modeled and analyzed by means of a rigid-plastic two-dimensional finite element method. Multi-pass rolling is performed in two different manners; the feeding direction of samples into the DCAP-channel is maintained in Route A and the feeding direction is reversed in the Route B. The deformation of AA1100 sheets during the DCAP process comprises three distinct processes of rolling, bending and shearing. The shear deformation of an amount of 0.5 was concentrated at the corner of the DCAP-channel where the abrupt change in the direction of material flow occurred. Because differences in the shear deformation in Route A and Route B led to the different strain states throughout the thickness of the aluminum sheet, the strain history in the DCAP-channel was analyzed in various thickness layers by the shear and effective strain components.

Analysis of the stress-strain state of copper M0B under different schemes of equal channel angular pressing and its effect on the structure and physical and mechanical properties

2019 ◽  
pp. 47-53
Author(s):  
L. F. Sennikova ◽  
G. K. Volkova ◽  
V. M. Tkachenko
Keyword(s):  
Equal Channel Angular Pressing ◽  
Strain State ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Stress Strain ◽  
Loading Pattern ◽  
Stress Strain State ◽  
Angular Pressing ◽  
Fine Copper ◽  
Copper Structure

The results of studies of the stress-strain state of copper M0b after deformation under different schemes of equal channel angular pressing (ECAP) are presented. The level of macro and micro stresses in copper has been determined in various ECAP modes. It is shown that the strength properties, deformation porosity and parameters of the fine copper structure differ depending on the loading pattern.

Duplex Spread Blade Method for Cutting Hypoid Gears with Modified Tooth Surface

1998 ◽  
Vol 120 (3) ◽  
pp. 441-447 ◽  
Author(s):  
K. Kawasaki ◽  
H. Tamura
Keyword(s):  
Cutting Edge ◽  
Tooth Surface ◽  
Radius Of Curvature ◽  
Large Radius ◽  
Ring Gear ◽  
Circular Arc ◽  
Hypoid Gears ◽  
Manufacturing Method ◽  
Straight Line

In this paper, a duplex spread blade method for cutting hypoid gears with modified tooth surface is proposed. The duplex spread blade method provides a rapid and economical manufacturing method because both the ring gear and pinion are cut by a spread blade method. In the proposed method, the nongenerated ring gear is manufactured with cutting edge that is altered from the usual straight line to a circular arc with a large radius of curvature and the circular arc cutting edge produces a modified tooth surface. The pinion is generated by a cutter with straight cutting edges as usual. The main procedure of this method is the determination of the cutter specifications and machine settings. The proposed method was validated by gear manufacture.

Résonateur ouvert en géométrie sphérique

1980 ◽  
Vol 58 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Gilles Duret ◽  
Gérard Zepp ◽  
Alain Wick
Keyword(s):  
Radius Of Curvature ◽  
Large Radius ◽  
Open Resonators

Most of the approximate theories of the spherical open resonators are insufficient, except for the very large radius of curvature. It is often necessary to consider other cases. The theory we have developed is applicable for any curvature and aperture of the mirrors. This theory also allows study of multi-dielectric cavities. This method is accurately studied in detail in this paper.

Improvement of nonmonotone deformation technology in plastic metal working

2021 ◽  
pp. 115-122
Author(s):  
S.M. Vaytsekhovich ◽  
Yu.V. Vlasov ◽  
A.Yu. Zhuravlev
Keyword(s):  
Experimental Investigation ◽  
Simple Shear ◽  
Strain State ◽  
Effectiveness Evaluation ◽  
Inhomogeneous Body ◽  
Metal Working ◽  
Practical Application ◽  
Angular Pressing ◽  
Plastic Metal ◽  
Rational Sequence

The production of semi-finished products made of refractory metals is considered. The advantage of parts production using combination of two types of straining with change in the straining direction: direct extrusion and equal-channel pressing is shown. The experimental investigation data of pure and simple shear for the semi-finished products processing made of tungsten and molybdenum are presented. Requirements for the tool providing diagonal flow and angular straining are formulated based on the analysis of the stress-strain state of the processes of axial symmetric extrusion and simple shear of plastically inhomogeneous body. Effectiveness evaluation of the combination of various types of fixtures and the rational sequence for using of diagonal flow and angular pressing is given. Experimental devices for practical application of the proposed technology are developed.

Finite Element Simulation of Aluminum ECAP Material Flow

2013 ◽  
Vol 423-426 ◽  
pp. 267-270
Author(s):  
Jian Hui Li ◽  
Zu Jian Yu ◽  
Da Zhi Xiao ◽  
Li Ping Zhang
Keyword(s):  
Finite Element ◽  
Material Flow ◽  
Maximum Principal Stress ◽  
Metallic Materials ◽  
Rigid Plastic ◽  
Ecap Processing ◽  
Angular Pressing ◽  
Fine Grain ◽  
Corner Flow ◽  
Element Simulation

To enhancing strength and toughness of metals, severe plastic deformation (SPD) grain refinement was a typical method. As one of the SPD method, equal channel angular pressing is an effective method in fabricating ultra-fine grain metallic materials. In this paper, the rigid-plastic finite element method was used to analyze the aluminum alloy ECAP processing, to reveal the material flow character and its effect on microstructure evolution. The simulation results were agreed with plastic mechanics and experiment well, and it was shown that distribution of maximum principal stress was not uniform, material located at the front-end of sample flow easily and material located at the top of die channel corner flow difficultly.

Experimental and Computational Investigation of Shaped Film Cooling Holes Designed to Minimize Inlet Separation

2020 ◽  
Author(s):  
Fraser B. Jones ◽  
Dale W. Fox ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Velocity Ratio ◽  
Tangential Velocity ◽  
Velocity Fields ◽  
Radius Of Curvature ◽  
Large Radius ◽  
Combustion Gases ◽  
Shaped Hole ◽  
Manufacturing Technologies ◽  
Film Cooling Holes

Abstract Film cooling is used to protect turbine components from the extreme temperatures by ejecting coolant through arrays of holes to create an air buffer from the hot combustion gases. Limitations in traditional machining meant film cooling holes universally have sharp inlets which create separation regions at the hole entrance. The present study uses experimental and computational data to show that these inlet separation are a major cause of performance variation in crossflow fed film cooling holes. Three hole designs were experimentally tested by independently varying the coolant velocity ratio (VR) and the coolant channel velocitty ratio (VRc) to isolate the effects of crossflow on hole performance. Leveraging additive manufacturing technologies, the addition of a 0.25D radius fillet to the inlet of a 7-7-7 shaped hole is shown to significantly improve diffuser usage and significantly reduce variation in performance with VRc. A second AM design used a very large radius of curvature inlet to reduce biasing caused by the inlet crossflow. Experiments showed that this “swept” hole design did minimize biasing of coolant flow to one side of the shaped hole and it significantly reduced variations due to varying VRc. RANS simulations at six VR and three VRc conditions were made for each geometry to better understand how the new geometries changed the velocity field within the hole. The sharp and rounded inlets were seen to have very similar tangential velocity fields and jet biasing. Both AM inlets created more uniform, slower velocity fields entering the diffuser. The results of this paper indicate large improvements in film cooling performance can be found by leveraging AM technology.

G203 Aerodynamic Sound Generated by Bend Round Bars with Large Radius of Curvature

2007 ◽  
Vol 2007 (0) ◽  
pp. _G203-1_-_G203-4_
Author(s):  
Hiroki MATSUMOTO ◽  
Ken-ichi SAITOH ◽  
Tetsuya YOSHIDA
Keyword(s):  
Radius Of Curvature ◽  
Large Radius ◽  
Aerodynamic Sound

Depth‐focusing analysis using a wavefront‐curvature criterion

Geophysics ◽  
1993 ◽  
Vol 58 (8) ◽  
pp. 1148-1156 ◽  
Author(s):  
Scott MacKay ◽  
Ray Abma
Keyword(s):  
Seismic Energy ◽  
Radius Of Curvature ◽  
Large Radius ◽  
Data Set ◽  
Depth Migration ◽  
Amplitude Data ◽  
Zero Radius ◽  
Inverse Radius ◽  
Interpretation Process ◽  
Zero Offset

Depth‐focusing analysis (DFA), a method of refining velocities for prestack depth migration, relies on amplitude buildups at zero offset to determine the extrapolation depths that best focus the migrated data. Unfortunately, seismic energy from dipping interfaces, diffractions, and noise often produce spurious amplitude indications of focusing. To reduce possible ambiguity in the DFA interpretation process, we introduce a new attribute for determining focusing that is relatively independent of amplitude. Our approach is based on estimates of the radius of wavefront curvature. The estimates are derived from normal moveout analysis of nonzero‐offset data saved during migration. By relating steeper moveout to smaller radius of wavefront curvature, focusing is defined by a wavefront curvature of zero radius. Additionally, we show that applying inverse‐radius weights to the amplitude data attenuates nonfocused events due to their large radius of curvature. Using the Marmousi data set, our weighting scheme resulted in reduced spurious focusing and enhanced velocity resolution in DFA.

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