Computer Application to the Visioplasticity Method

1967 ◽  
Vol 89 (2) ◽  
pp. 339-346 ◽  
Author(s):  
A. Shabaik ◽  
S. Kobayashi
Keyword(s):  
Plane Strain ◽  
Complete Solution ◽  
Effective Strain ◽  
Cone Angle ◽  
Extrusion Process ◽  
Axisymmetric Deformation ◽  
Extrusion Ratio ◽  
Computer Application ◽  
White Lead ◽  
Pure Lead

Procedures for using a computer for the complete solution to plane strain as well as axisymmetric deformation problems have been developed. The velocity, strain rate, total effective strain, and stress distributions were obtained for two commercially pure lead specimens extruded in a forward extrusion process using white lead in oil as a lubricant. The axisymmetric extrusion was carried out at a speed of 1/8 ipm through a conical die having a 45 deg half-cone angle with a 2:1 extrusion ratio, and the plane-strain extrusion through a tapered die having a 45 deg half-taper angle with a 1.66:1 extrusion ratio.

The Effect of Process Variables on Extrusion Pressures of Lead

1959 ◽  
Vol 81 (3) ◽  
pp. 207-214 ◽  
Author(s):  
J. Frisch ◽  
E. G. Thomsen
Keyword(s):  
Room Temperature ◽  
Extrusion Ratio ◽  
Extrusion Pressure ◽  
White Lead ◽  
Cylinder Wall ◽  
Process Variables ◽  
Pure Lead ◽  
Commercially Pure ◽  
Wide Range

Billets of commercially pure lead, 2 in. diam × 3 in. long were extruded at room temperature through five different die contours at ram speeds up to 50 ipm. It was found that, for the direct and indirect extrusions, with good lubrication (white lead in oil) and with good cylinder-wall finish, the extrusion pressure-displacement diagrams were essentially the same. The concentric and eccentric single-bar and multibar extrusions at constant extrusion ratio required approximately the same pressures when extruded at identical speeds. The extrusion pressures over the wide range of speeds investigated showed approximate linearity when plotted on log-log co-ordinates.

Three-Dimensional Analysis of Extrusion Process Utilizing the Physical Modeling Technique

1993 ◽  
Vol 115 (1) ◽  
pp. 32-40 ◽  
Author(s):  
H. Sofuog˜lu ◽  
J. Rasty
Keyword(s):  
Physical Modeling ◽  
Cone Angle ◽  
Three Dimensional ◽  
Extrusion Process ◽  
Extrusion Ratio ◽  
Modeling Technique ◽  
Modeling Material ◽  
Internal Deformation ◽  
Metal Extrusion ◽  
Deformation Patterns

The purpose of this study was to simulate the metal extrusion processes via three-dimensional physical modeling technique. Plasticine was utilized as the modeling material, while plexiglass was incorporated in the design and fabrication of a labscale extrusion apparatus. The extrusion setup was designed to accommodate dies of different semi-cone angle while also making it possible to change the extrusion ratio R = A0/Af. Cylindrical billets were prepared utilizing alternating layers of two colors of plasticine. Extrusion of cylindrical billets was conducted at three different reduction ratios and three different die angles for each reduction ratio. Dissection of the extruded billets along a centroidal plane revealed the internal deformation patterns which were subsequently utilized for determining the effect of the die angle and extrusion ratio on the state of strain in the final product as well as the required extrusion loads.

Simulation of Influence of Friction Coefficient on Extrusion of TC4 Alloy

2013 ◽  
Vol 470 ◽  
pp. 244-249
Author(s):  
Chang Dong Liu ◽  
Yi Du Zhang
Keyword(s):  
Friction Coefficient ◽  
Strain Rate ◽  
Effective Strain ◽  
High Stress ◽  
Extrusion Process ◽  
Extrusion Pressure ◽  
Tc4 Alloy ◽  
Stress Zone ◽  
D Model ◽  
High Stress Zone

Based on Simufact11.0, a 3-D model of T profile extrusion is established and the extrusion process of TC4 is investigated using finite volumemethod(FVM) of Euler mesh description. Effects of different friction coefficients on the effective stress, extrusion pressure, effective strain and effective strain rate have been studied. The study shows that there is a high-stress zone at a certain distance from the entrance of the forming area and a high strain rate zone around that area. With the increase of friction coefficient, the value of the stress increased and the deformation is more uneven. The track of extrusion pressure shows that extrusion increase with the increase of friction coefficient.

Comparison of Two Complete Solutions in an Axisymmetric Extrusion With Experiment

1969 ◽  
Vol 91 (3) ◽  
pp. 543-548 ◽  
Author(s):  
A. H. Shabaik ◽  
E. G. Thomsen
Keyword(s):  
Strain Rate ◽  
Effective Strain ◽  
Cone Angle ◽  
Low Friction ◽  
First Approximation ◽  
Strain And Strain Rate ◽  
Conical Die ◽  
Stream Lines ◽  
Half Cone ◽  
Half Cone Angle

An upper-bound and a potential solution to a forward extrusion problem were compared with experimental results obtained by the visioplasticity method. The process consisted of extruding a 2-in-dia billet of preforged lead through a conical die having a half-cone angle of 45 deg under the condition of relatively low friction. The comparison was made for steady state stream lines, velocities, strain rate components, effective strain and strain rate, grid distortion, and stress distribution. It was found that the curves were generally of similar shape and that some differences existed in magnitude only. It is suggested that the theoretical solutions can be used to advantage to a first approximation in predicting all important variables.

Stresses and Displacements in an Elastic-Plastic Wedge

1957 ◽  
Vol 24 (1) ◽  
pp. 98-104
Author(s):  
P. M. Naghdi
Keyword(s):  
Plane Strain ◽  
Isotropic Material ◽  
Complete Solution ◽  
Normal Pressure ◽  
Stress Strain ◽  
Included Angle ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Plastic Domain ◽  
Elastic Perfectly Plastic

Abstract An elastic, perfectly plastic wedge of an incompressible isotropic material in the state of plane strain is considered, where the stress-strain relations of Prandtl-Reuss are employed in the plastic domain. For a wedge (with an included angle β) subjected to a uniform normal pressure on one boundary, the complete solution is obtained which is valid in the range 0 < β < π/2; this latter limitation is due to the character of the initial yield which depends on the magnitude of β. Numerical results for stresses and displacements are given in one case (β = π/4) for various positions of the elastic-plastic boundary.

scholarly journals Development of a novel high straining backward extrusion process

2018 ◽  
Vol 190 ◽  
pp. 06001 ◽  
Author(s):  
Qiang Wang ◽  
Zhimin Zhang ◽  
Xubin Li ◽  
Huifang Zhang
Keyword(s):  
Flow Direction ◽  
Effective Strain ◽  
Fibrous Tissue ◽  
Axial Direction ◽  
Extrusion Process ◽  
Backward Extrusion ◽  
New Process ◽  
Processed Sample ◽  
The Difference ◽  
Low Performance

In this study, a new method of backward extrusion is proposed. In this new process, a punch with a movable mandrel was designed. A hollow billet was firstly backward extruded and subsequently upset with the use of the punch after the mandrel returned. The extrusion and upsetting processes were successively executed in order for a higher effective strain to be imposed and a fibrous tissue flow direction to be controlled. In order for the capability of this process to be investigated, experimental and finite element (FE) methods were used. The effective strain of the final part prepared by both the conventional and the new process were compared along the bottom radial and wall axial direction respectively. In the results, it is shown that the plastic strain applied through the processed sample was approximately higher in twice the value of the sample processed via conventional backward extrusion. Consequently, this may improve the mechanical properties and anisotropy of the final products. The difference of the UTS and the TYS between radial and tangential at the bottom was less than 3%.This new process has proven to be promising for parts with a central hole at the bottom production in order for the parts low performance to be improved.

Deformation Behaviors of Non-Metallic Inclusion in FGH96 Superalloy during Different Plastic Processes

2012 ◽  
Vol 538-541 ◽  
pp. 1187-1191
Author(s):  
Min Cong Zhang ◽  
Chen Yi Liu ◽  
Shu Yun Wang
Keyword(s):  
Transition Zone ◽  
Extrusion Direction ◽  
Extrusion Process ◽  
Extrusion Ratio ◽  
Metallic Inclusion ◽  
Isothermal Forging ◽  
Forging Process ◽  
Discontinuous Line ◽  
Metallic Inclusions ◽  
Deformation Behaviors

The non-metallic inclusions in FGH96 superalloy during different plastic processes were studied. The results show that SiO2 react with aluminum and titanium in FGH96 superalloy and the reaction zone is formed in the interface between SiO2 and alloy, whereas Al2O3 react with no elements in FGH96 superalloy and the transition zone between them is mechanical combination during the plastic processes. In addition the sizes of non-metallic inclusions increase in the direction perpendicular to deformation during isothermal forging process. The non-metallic inclusions are pulled into a discontinuous line in extrusion direction and areas of non-metallic inclusions in each direction are constricted during extrusion process. The non-metallic inclusions of FGH96 superalloy is conditioned by the state of the as-extrusion inclusions during extrusion+isothermal forging process. In summary, extrusion process with large extrusion ratio can break the non-metallic inclusions in FGH96 alloy effectively and improve forging quality.

SIMULATION OF FINAL DIRECT EXTRUSION STAGE FOR LARGE RODS WITH LOW EXTRUSION RATIO

2018 ◽  
pp. 48-55
Author(s):  
V. R. Kargin ◽  
A. Yu. Deryabin
Keyword(s):  
Defect Formation ◽  
Cone Angle ◽  
Metal Flow ◽  
Joint Effect ◽  
Extrusion Ratio ◽  
Contact Friction ◽  
Extrusion Force ◽  
Direct Extrusion ◽  
Negative Effect ◽  
Edge Temperature

The direct extrusion of large 7075 alloy bars 188, 214, 252, 283, 326, 560 mm in diameter was simulated with 0 and 0,5 friction coefficients, 80° and 90° die cone angles from the 800 mm diameter container at the 200 MN press using the DEFORM-2D software package. It provided the distribution of metal flow radial velocities on the dummy block working surface versus the contact friction value, die cone angle and extrusion ratio factor at the main and final stages of extrusion. Butt-end height at the beginning of back-end extrusion defect formation was taken equal to a distance between the dummy block plane and the plane of extruded metal feeding into flat or cone die openings. The joint effect of the extrusion ratio factor, friction coefficient and die cone angle on the butt-end height, extrusion force, deformation and stress intensity factors, and die opening edge temperature was studied. Numerical experiments were performed based on the 23 complete factorial design for the following parameter variability intervals: Х1 = 3÷9, Х2 = 0÷0,5, Х3 = 80÷90°. Friction between the tool and the blank at the final extrusion stage has a negative effect due to a noticeable radial velocity reduction. This leads to the earlier initiation of central back-end extrusion defect formation. Extrusion into the conical die and increasing the extrusion ratio factor, on the contrary, speeds up radial flow velocity and ensures that the back-end extrusion defect starts forming later. The main factor that determines butt-end height is the extrusion ratio factor. A mathematical model is proposed to select the butt-end thickness for specific conditions of extruding large bars with low extrusion ratios.

Die Cone Angle Optimization in Forward Extrusion Process

2014 ◽  
Vol 2 (1) ◽  
pp. 39-43
Author(s):  
Ali Jabbari ◽  
Armaghan Akbari Farahani
Keyword(s):  
Cone Angle ◽  
Extrusion Process ◽  
Forward Extrusion

Numerical Simulation of Aluminum Extrusion Process Using Body-Fitted Grids Based Finite Volume Method

2014 ◽  
Vol 602-605 ◽  
pp. 64-68
Author(s):  
Yu Jie Zhang ◽  
Xiao Feng Gong ◽  
Rui Wang ◽  
Xiao Qing Feng
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Initial Conditions ◽  
Effective Strain ◽  
Mathematic Model ◽  
Extrusion Process ◽  
Aluminum Extrusion ◽  
Computational Region ◽  
Coordinate Conversion ◽  
Volume Method

A mathematic model of aluminum extrusion process using body-fitted grids based finite volume method was studied and established in this paper. The basic goverment equations of the finite volume method were built, body-fitted grids were used to mesh computational region, basic goverment equations were discretized on body fitted grids directly, so complex coordinate conversion was avoided by no use of aptamer coordinate system. Initial conditions, boundary conditions and calculation processes of aluminum extrusion process finite volume method were studied and established, a program had been written based this model and a typical process of aluminum extrusion was simulated, amount of physical fields such as velocities, effective stress and effective strain rate etc. were obtained, the results were compared with that simulated by finite element method, so the feasibility and exactness of the mathematic model is proved.

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