An analysis for three-dimensional upset forging of elliptical disks and rings based on the upper-bound method

2020 ◽  
Vol 183 ◽  
pp. 105835 ◽  
Author(s):  
Shu-peng Cai ◽  
Zhong-jin Wang
Keyword(s):  
Upper Bound ◽  
Three Dimensional ◽  
Upper Bound Method ◽  
Upset Forging

Three Dimensional Upper Bound Modelling for Extrusion of Round-to-Octagon Section Using Linearly Converging Die

2009 ◽  
Vol 424 ◽  
pp. 189-196
Author(s):  
Kali Pada Maity ◽  
Akshaya Kumar Rout
Keyword(s):  
Cross Section ◽  
Upper Bound ◽  
Regular Polygon ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Upper Bound Method ◽  
Equal Area ◽  
Admissible Velocity ◽  
Round Billet ◽  
Die Geometry

The extrusion of section from round billet poses a great challenge for theoretical modeling of the process using upper bound method. The greatest difficulty in three-dimensional upper bound method is to determine kinematically admissible velocity field. The SERR (Spatial Elementary Rigid Region) technique is fairly applicable for analyzing extrusion of sections having re-entrant corners. A modified version of SERR technique has been used for extrusion of octagon sections from round billet through a linearly converging die. The circular cross section of the round billet is approximated by a regular polygon of equal area. The extrusion pressure has been computed for different boundary condition at the die billet interface. The optimum die geometry has been determined.

Upper-bound solutions of three-dimensional passive earth pressures

2005 ◽  
Vol 42 (5) ◽  
pp. 1449-1460 ◽  
Author(s):  
S Škrabl ◽  
B Macuh
Keyword(s):  
Failure Mechanism ◽  
Upper Bound ◽  
Limit Analysis ◽  
Central Body ◽  
Three Dimensional ◽  
Failure Surface ◽  
Outer Side ◽  
Soil Pressure ◽  
Upper Bound Method ◽  
The Cross

This paper presents a novel approach to the determination of passive soil pressures: using the upper-bound method within the framework of limit analysis theory. It is based on a three-dimensional, kinematically admissible, rotational, hyperbolical failure mechanism. The failure mechanism is composed of the central and two lateral bodies, which are connected by a common velocity field. This approach is similar to two-dimensional stability analyses, where the log spiral potential failure surface is considered. The front surface of the central body interacts with the retaining wall; the upper surface can be loaded by surcharge loading; and the log spiral segment defines the curved failure surface of the central part. The cross sections of the lateral bodies are in agreement with the cross section of the central body. On the outer side, they are laterally bounded by a curved and kinematically admissible hyperbolic surface, which is defined by enveloping the hyperbolical half cones and part of the case surface of the leading half cone. The results give values for the passive soil pressure coefficients that are for most cases lower than the values determined by the upper-bound method of limit analysis for a translational failure mechanism, as published in the literature.Key words: limit analysis, earth pressure, passive pressure, failure surface, soil–structure interaction.

An Analysis of Three-Dimensional Upset Forging of Regular Polygonal Blocks by Using the Upper-Bound Method

1987 ◽  
Vol 109 (2) ◽  
pp. 155-160 ◽  
Author(s):  
D. Y. Yang ◽  
J. H. Kim
Keyword(s):  
Velocity Field ◽  
Upper Bound ◽  
Pure Copper ◽  
Three Dimensional ◽  
Total Power ◽  
Total Power Consumption ◽  
Upset Forging ◽  
Theoretical Predictions ◽  
Forging Load ◽  
Good Agreement

A simple kinematically admissible velocity field for three-dimensional deformation in upset forging of regular polygonal blocks is proposed which takes into account the sidewise spread as well as the bulging along thickness. From the proposed velocity field the upper-bound load and the deformed configuration are determined by minimizing the total power consumption with respect to three chosen parameters. Experiments are carried out with annealed commercially pure copper at room temperature for different thicknesses, billet shapes and lubrication conditions. The theoretical predictions both in the forging load and the deformed configuration are in good agreement with the experimental results. It is thus shown that the velocity field proposed in this work can be conveniently used for the prediction of the forging load and deformation in the upset forging of regular polygonal blocks.

Sign in / Sign up

Export Citation Format

Share Document