关键词: 正挤压, 刚塑性有限元, 韧性破坏, 表面裂纹, 缩孔

Abstract:

In this paper, the rigid-plastic finite element method is applied to simulate the axi-symmetric forward extrusion processes with cone and flat dies.Extrusion forces,distributions of the stress and strain fields during extrusion, and the phenomenon of the two-peaks on the front end of the product, etc.are studied with the computing program.Moreover, the program is also used to simulate and analyse the cavity and the surf ace crack during extrusion.Some curves and data for prediction of the above-mentioned defects have been worked out.Some improvements have been made in the calculation of the rigid-plastic finite element.For example, new techniques for handling the singularity in the eight-nodes quadrilateral mesh and for tracking the movement of a certain particle are proposed.Experiments show that the computed results agree rather well with the experimental data.

Key words: forward extrusion, rigid-plastic finite element, ductile fracture, surface crack, cavity