Abstract: Based on the balance equation and the plastic condition, applied the rigid-plastic mechanical model and used the actual test - pieces shape as the boundary condition, the problem of numerical simulation of the stress field upsetting the cylinder (H/D >1) between normal platens is solved. The internal stress field of the cylinder under the high diameter ratio is 2.33 and the range of deformation from 15 % ~50 % is obtained. The result of simulation tallies with the qualitative experiment of the physics simulation, and the tension stress theory of the rigid-platic mechanical model is more perfective.

Key words: Cylinder, Numerical simulation, Stress field, Upsetting