Plane strain extrusion through curved dies: an upper bound analysis and FEM simulation

Extrusion is a process used to create objects with uniform cross-sectional profile. A material is pushed through a die of the desired cross-section. In this process, a like other metal forming process, calculating and optimization of the extrusion force is important. Among various methods of solution to metal forming processes, the upper bound technique as an analytical method and finite element method has been widely used for the analysis of the metal forming processes effectively. In this paper, plane strain forward extrusion through an arbitrary die profile was analyzed by upper-bound approach in cylindrical coordinate system and the general velocity field for die with any shape is presented. Deformation zone divided into three deformation zones and the amounts of strain rate in each deformation zone were calculated by exhibiting an admissible velocity field in cylindrical coordinate system. Then, the internal power, the power dissipated on frictional and velocity discontinuity surfaces were obtained and then, the extrusion force and average extrusion pressure was calculated. . The extrusion process was simulated by finite element method (FEM). Analytical results were compared with the results given by finite element method (Abaqus software) for curved dies and wedge shaped die. These comparisons showed a good agreement bysimulation results. In addition, the effects of various parameters on relative average extrusion pressure were investigated.

کلیدواژه ها:

Plane strain extrusion ، Upper bound ، FEM