this paper deals with three-dimensional evaluation of the slopes on the basis of limit analysis. an upper-bound technique of limit analysis is used in this paper to determine either the bearing capacity of a shallow foundation near a slope or the safety factor of the slope. the theorems of limit analysis (upper and lower bound) provide a powerful tool for solving problems in which limit loads n...

Steady state axisymmetric deformations of a viscoplastic target being penetrated by a rigid cylindrical penetrator with a hemispherical nose are analyzed. The presumed kinematically admissible velocity field satisfies all of the boundary conditions on the target/penetrator interface, and also the balance of mass. The unknown parameters appearing in the admissible velocity field are found by min...

Precision forging process is widely used for the production of spur gears due to its advantages such as improved strength and surface finish, little waste of materials and reduction in the machining time of the gear. An important aspect of precision forging process is the load required to perform the process successfully and design the forging tools. In this research, a new kinematically admiss...

Vortex extrusion (VE) is a severe plastic deformation technique which is based on the synergies between high strain accumulation and high hydrostatic pressure. Such a high amount of pressure, places a mandate to seek the method for investigation of the load under processing conditions. For this, kinematically admissible velocity field and upper bound terms based on Bezier formulation are develo...

In this research, flat rolling process of bonded sandwich sheets is investigated by the method of upper bound. A kinematically admissible velocity field is developed for a single layer sheet and is extended into the rolling of the symmetrical sandwich sheets. The internal, shear and frictional power terms are derived and they are used in the upper bound model. Through the analysis, the rolling ...

An upper bound method for the process of plane strain extrusion through a wedge-shaped die is derived. A technique for constructing a kinematically admissible velocity field satisfying the exact asymptotic singular behavior of real velocity fields in the vicinity of maximum friction surfaces (the friction stress at sliding is equal to the shear yield stress on such surfaces) is described. Two s...

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...

The present paper considers the wire drawing process through a conical die and provides an approximate solution for force, assuming arbitrary hardening law. is based on upper bound theorem. However, this theorem does not apply to stationary flow of strain-hardening materials. Therefore, adopted engineering approach replace original material model with non-homogeneous, perfectly plastic model. k...