In this paper, a generalized expression for the flow field in axisymmetric extrusion process is suggested to be valid for any dies and the boundary shapes of the plastic deformation zone. The general power terms are derived and the extrusion force is calculated by applying upper bound technique for a streamlined die shape and exponential functions for shear boundaries. It is shown that assuming...

In this research, optimization process of axisymmetric extrusion dies is proposed. Plastic zone is analyzed using finite element method in the Eulerian system with flow formulation. The die profiles are defined by Bezier curves with six control points. Two effective functions are considered in this research; standard deviation of the strain rate and the rate of energy consumption during extrusi...

many metal forming problems have been solved using the slip line field method but all of them have either been two-dimensional (plane strain or plain stress) or axisymmetric problems. in this paper a procedure has been proposed by which the slip line field solution to three dimensional problems of metal forming becomes possible. for this purpose the extrusion of shaped sections has been taken a...

Many metal forming problems have been solved using the slip line field method but all of them have either been two-dimensional (plane strain or plain stress) or axisymmetric problems. In this paper a procedure has been proposed by which the slip line field solution to three dimensional problems of metal forming becomes possible. For this purpose the extrusion of shaped sections has been taken a...

This paper describes an upper bound analysis of cold forward extrusion of spur gears with modified tooth profile. Spur gear geometrical parameters such as module, number of teeth, pressure angle, bore radius and addendum modification factor were input to a computer program written in Visual Basic. Then spur gear, billet and extrusion die cavity were modeled automatically in SolidWorks. For uppe...

The effects of hydrostatic extrusion on particle cracking and on the subsequent tensile properties of some prototypical particlereinforced metal–matrix composites are investigated. In most cases, tensile failure occurs through a plastic instability in accordance with the Considere criterion for necking. The corresponding failure strain is therefore dictated by the global flow and hardening char...

This study formulates a universal velocity ®eld that is kinematically admissible for application in the extrusion of non-axisymmetric rods. Then upper bound theorem dictates that a better upper bound solution heavily depends on the precise conformity of the velocity ®eld postulated. However, a compromise must frequently be made, since the formulation is in general rather complicated. The kinema...

slab method of analysis has been used for solving metal forming problems for a long time. however it has been restricted to plane strain and axisymmetric problems due to limitations in its formulations. in this paper a new formulation has been proposed so that it could be applied to three dimensional problems in metal forming. a parametric slab has been considered in this analysis and the force...