Comparison of Slip-Line Solutions With Experiment

1956 ◽  
Vol 23 (2) ◽  
pp. 225-230
Author(s):  
E. G. Thomsen
Keyword(s):  
Plane Strain ◽  
Pure Aluminum ◽  
Maximum Shear Stress ◽  
Yield Condition ◽  
Approximate Solutions ◽  
Extrusion Process ◽  
Experimental Results ◽  
Wall Friction ◽  
Axially Symmetric ◽  
Area Reduction

Abstract Plane-strain and axially symmetric approximate solutions for a perfect plastic are compared with experimental results obtained from the extrusion of a billet of commercially pure aluminum. The extrusion process was carried out at room temperature under essentially negligible external wall friction with a reduction of area of 87.8 per cent. It is found that the plane-strain solution is in good agreement with the experimental results, if a constant k = σ̄/2 = 20,000 psi (maximum shear stress for Tresca’s criterion) is substituted in the plane-strain solution. The flow stress (σ̄ ≅ 40,000 psi) was determined from a property test for the aluminum billet, at a strain equivalent to the uniform deformation in the extrusion (i.e., same area reduction without shear deformation). It is found that the Haar and von Karman yield condition is not valid for the present case, and further that the axially symmetric solution demonstrates no real advantage over the simpler plane-strain solution in predicting the stress distribution in an axially symmetric extrusion problem.

Evaluation of Paraffinic Mineral Oil as Lubricant in Cold Work Extrusion Process

2014 ◽  
Vol 554 ◽  
pp. 327-331 ◽  
Author(s):  
Samion Syahrullail ◽  
Mohd Ahyan Nurul Aini
Keyword(s):  
Plane Strain ◽  
Pure Aluminum ◽  
Cold Work ◽  
Extrusion Process ◽  
Mineral Oil ◽  
Experimental Result ◽  
Friction Effect ◽  
Billet Material ◽  
Deformation Area ◽  
Taper Die

In this paper, the effect of frictional constraint from the application of three different viscosity of additive free paraffinic mineral oil as lubricant were investigated by cold work forward plane strain extrusion experiments. The experiment used a cold work plane strain extrusion apparatus consist of a pair of taper die and a symmetrical workpiece (billet). The billet material was annealed pure aluminum A1100 with radius 5 mm in deformation area. The experimental result shows that the higher viscosity, will lead to lower friction effect to the deformed area, as well as product area.

Line Contact Deformation: A Cylinder Between Two Flat Plates

1981 ◽  
Vol 103 (1) ◽  
pp. 21-25 ◽  
Author(s):  
M. R. Hoeprich ◽  
H. Zantopulos
Keyword(s):  
Plane Strain ◽  
General Equation ◽  
Roller Bearing ◽  
Experimental Results ◽  
Line Contact ◽  
Contact Deformation ◽  
Flat Plates ◽  
Special Cases ◽  
Analytical Work

Various line contact deformation equations used in roller bearing technology are analyzed. Many of these deformation equations, primarily involving plane strain, are shown to be special cases of a general equation derived in this paper. Experimental results are also presented to support the results of the analytical work.

Stress Distribution in a Uniformly Rotating Equilateral Triangular Shaft

1955 ◽  
Vol 22 (2) ◽  
pp. 255-259
Author(s):  
H. T. Johnson
Keyword(s):  
Approximate Solution ◽  
Stress Distribution ◽  
Boundary Conditions ◽  
Plane Strain ◽  
Cross Section ◽  
Plane Stress ◽  
Biharmonic Equation ◽  
Approximate Solutions ◽  
Distribution Of Stresses ◽  
General Method

Abstract An approximate solution for the distribution of stresses in a rotating prismatic shaft, of triangular cross section, is presented in this paper. A general method is employed which may be applied in obtaining approximate solutions for the stress distribution for rotating prismatic shapes, for the cases of either generalized plane stress or plane strain. Polynomials are used which exactly satisfy the biharmonic equation and the symmetry conditions, and which approximately satisfy the boundary conditions.

Research of stamping of unequal channel bars. Part 5. Methods for calculating the extrusion of channels. 2. Extrusion of non-strengthening material

2021 ◽  
pp. 46-52
Author(s):  
A.L. Vorontsov
Keyword(s):  
Plane Strain ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
High Accuracy ◽  
Experimental Results ◽  
Die Forging

The results of experimental studies on the extrusion of channels from non-strengthening material are presented. Comparison of theoretical calculations with experimental results showed the high accuracy of the derived formulas. Keywords: die forging, extrusion, punch, matrix, misalignment, plane strain. [email protected]

A Study of Multiple Hole Extrusion

1979 ◽  
Vol 101 (2) ◽  
pp. 135-138
Author(s):  
Amit Bagchi ◽  
John G. Lenard
Keyword(s):  
Velocity Field ◽  
Mathematical Models ◽  
Maximum Power ◽  
Experimental Results ◽  
Significant Parameter ◽  
Area Reduction

Two mathematical models proposed by Avitzur and valid for axially symmetrical square extrusion are tested for their ability to predict the maximum power required in single as well as multiple hole extrusion. Comparison to experimental results obtained using plumber’s lead shows good correlation. The most significant parameter is shown to be the total area reduction. The velocity field in multiple hole extrusion—which by necessity must be nonaxially symmetrical—appears not to affect the power required for extrusion.

Application of Spencer’s Ideal Soil Model to Granular Materials Flow

1976 ◽  
Vol 43 (1) ◽  
pp. 49-53 ◽  
Author(s):  
H. L. Morrison ◽  
O. Richmond
Keyword(s):  
Fluid Flow ◽  
Granular Materials ◽  
Plane Deformation ◽  
Yield Condition ◽  
Classical Equation ◽  
Maximum Flow ◽  
Approximate Solutions ◽  
Field Equations ◽  
Full Field ◽  
Materials Flow

In 1964, Spencer proposed a model for plane deformation of soils based upon the concept that the strain at any point may be considered as the resultant of simple shears on the two surface elements where Coulomb’s yield condition is met. Gravitation and acceleration terms were neglected in his full field equations. These terms are included in the present treatment, however, since they play an essential role in granular materials flow problems. It is shown that the field equations remain hyperbolic, and the characteristic equations are derived. In addition, a streamline equation, similar to Bernoulli’s classical equation for fluid flow, is derived and used together with the continuity equation to obtain one-dimensional approximate solutions to some typical hopper and chute problems. A solution is obtained for the nonsteady flow from a wedge-shaped hopper when the gate is suddenly opened, including an equation for the minimum slope necessary to prevent arching. Another solution is obtained for the profile of a hopper which has constant wall pressure. Still another solution is obtained for the relationship between the height of a chute and its exit velocity, and it suggests that the maximum trajectory usually is obtained with a horizontal exit since an upward-sloping exit requires a velocity jump at the minimum point in the chute, similar to a hydraulic jump in fluid flow. All of these solutions are ideal in the sense that they include no wall resistance to the flow, and therefore represent maximum flow rates.

DETERMINING ALTERNATIVES FOR METAL FORMING LUBRICANTS: A STUDY USING PLANE STRAIN COLD EXTRUSION PROCESS OF JIS-A1100 PURE ALUMINUM BILLET

2015 ◽  
Vol 74 (10) ◽  
Author(s):  
M. A. Nurul ◽  
S. Syahrullail ◽  
M. N. Musa
Keyword(s):  
Product Quality ◽  
Plane Strain ◽  
Renewable Resources ◽  
Metal Forming ◽  
Pure Aluminum ◽  
Cold Work ◽  
Cold Extrusion ◽  
Film Material ◽  
Ability To Act ◽  
Taper Die

Lubrication is very important in metal forming processes to control wear and friction at the interface between interacting surfaces. Non-renewable resources, such as plain mineral oils are widely used due to its ability to act as a supplier to wearing contacts; it may function as a film material or even sustain chemical transformations to become a film material. Since non-renewable resources can only last for more than a decade, renewable resources have been studied in order to find alternative lubricants that can present similar results in terms of extrusion load and product quality. Two renewable lubricants were analyzed (RBD palm olein and jatropha) together with an additive free paraffinic mineral oil, VG32, which acted as a reference lubricant. The experiment used a cold work plane strain extrusion apparatus that consists of a pair of taper die and a symmetrical work piece (billet). The billet material was made of annealed pure aluminum JIS-A1100 with radius of 5 mm in the deformation area. It was found that higher viscosity lubricants produced low extrusion load and friction during metal forming process with no major severe wear on product quality. Based on the results, it was proven that renewable resource based lubricants can be considered as a substitute for common lubricants used in the industry, since they present similar results with those currently applied in the industry. 

Microstructure and Mechanical Properties of Twist Extruded Pure Aluminum Processed by Post-Rolling

2011 ◽  
Vol 264-265 ◽  
pp. 183-187 ◽  
Author(s):  
S. Ranjbar Bahadori ◽  
Seyed Ali Asghar Akbari Mousavi ◽  
A.R. Shahab
Keyword(s):  
Grain Size ◽  
Pure Aluminum ◽  
Rolling Process ◽  
Extrusion Process ◽  
Ultrafine Grained ◽  
Twist Extrusion ◽  
Aluminum Sample ◽  
Deformation Processes ◽  
Ultrafine Grained Materials ◽  
Extrusion Method

Interest in processing of bulk ultrafine-grained materials has grown significantly over the last years. Severe plastic deformation processes such as twist extrusion have been the essence of these researches and used to decrease the bulk grain size. The bulk gain size can reduce if twist extrusion process combines with a conventional forming technique. In this study, the effects of reduction by employing the rolling process after the twist extrusion method were considered. The twist extrusion process of the commercially pure aluminum sample was carried out using a twisted die with 60º die angle, and the samples were processed through rolling subsequently. As a result of rolling, average microstructure grain size decreased significantly and the hardness amount increased accordingly

Investigation on the Effect of Geometrical Shape of Cold Direct Extrusion on Commercially Pure Aluminum Alloyed by 4% Cu

2015 ◽  
Vol 1105 ◽  
pp. 182-189 ◽  
Author(s):  
Adnan I.O. Zaid ◽  
S.M.A. Al-Qawabah
Keyword(s):  
Mechanical Behavior ◽  
Pure Aluminum ◽  
Extrusion Process ◽  
Control Area ◽  
Geometrical Shape ◽  
Compression Tests ◽  
Maximum Enhancement ◽  
Cross Sectional ◽  
Direct Extrusion ◽  
Cu Alloy

Al-4% Cu alloys are now widely used in many engineering applications especially in robotic, aerospace and vibration control area. The main problem arises from the weakness of their mechanical characteristics. Therefore, this study is directed towards enhancing the mechanical properties through severe plastic deformation, hence it is anticipated that cold direct extrusion process may enhance their mechanical behavior. This was performed through using three different cross sectional dies namely; circular, square, and rectangular that have the same cross sectional area. The general microstructure, microhardness, and compression tests were performed on each specimen produced before and after extrusion for Al and Al-4% Cu alloy. It was found that the maximum enhancement in mechanical behavior was achieved after extrusion through the rectangular shape for both Al and Al-4% Cu alloy at 0.2 strain by 143% for Al and 134.8% for Al-4%Cu wt.; similarly the hardness of both of them was improved where a maximum of 141.8 % was obtained for Al-4% Cu wt. in case of rectangular cross sectional die.

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