in this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. the deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a velocity field is presented which is different from velocity fields employed in previous studies. the total power consumption of the ...

presented is a method of two-dimensional analysis of the active earth pressure due to simultaneous effect of both soil weight and surcharge of strip foundation. the study’s aim is to provide a rigorous solution to the problem in the framework of upper-bound theorem of limit analysis method in order to produce some design charts for calculating the lateral active earth pressure of backfill when ...

although some 3d slope stability algorithms have been proposed in recent three decades, still role of pore pressures in three dimensional slope stability analyses and considering the effects of pore water pressure in 3d slope stability studies needs to be investigated. in this paper, a limit analysis formulation for investigation of role of the pore water pressure in three dimensional slope sta...

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 ...

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...

we consider online scheduling of jobs with speci c release time on m identical machines. each job has a weight and a size; the goal is maximizing total weight of completed jobs. at release time of a job it must immediately be scheduled on a machine or it will be rejected. it is also allowed during execution of a job to preempt it; however, it will be lost and only weight of completed jobs contr...

in the present paper, the deformation zone of the ecae (equal channel angular extrusion) process was investigated using the upper bound theorem. for this purpose, the shape of the streamlines in the deformation zone was assumed to be cubic bezier curves. then, the force required for the ecae process was optimized with regard to the parameters defining the shape of streamlines by the upper bound...

precision forging process is widely used for the production of spur gears due to its advantages such asimproved strength and surface finish, little waste of materials and reduction in the machining time ofthe gear. an important aspect of precision forging process is the load required to perform the processsuccessfully and design the forging tools. in this research, a new kinematically admissibl...