Modeling drawings of a cylinder detail without clipping a working flange from an isotropic and anisotropic metal

Abstract

The issue of drawing a cylindrical part without pressing the flange of a flat workpiece in the form of numerical simulation using the software package “Simullia Abaqus” is considered. In this case, isotropic and anisotropic sheet metal is modeled in order to identify the features of their deformation and the validity of assumptions in the analytical models of the isotropy of the material. It is shown that the distribution of stresses and strains for anisotropic and isotropic billets is identical. To conduct a qualitative analysis of the drawing processes, it is sufficient to limit itself to an isotropic metal model. This will greatly simplify the resulting analytical expressions and the time for interpreting the results. To clarify the solutions, it is necessary in mathematical models to take into account the anisotropy of the sheet stock, which will make it possible to identify areas of increased strength and ductility of the workpiece, as well as quantitatively predict thinning in a dangerous section. It is shown that the initial anisotropy increases the stiffness coefficient of the stress state scheme. This leads to a worsening of the deformation conditions and the exhaustion of the ductility resource earlier than for an isotropic billet. At the same time, the appearance of corrugations is accompanied by displacements and rotations of material points of the initially flat billet, however, for anisotropic billet, these displacements develop faster along the course of forming, but destruction of the billet may occur later due to the greater strength of the billet in thickness in comparison with the strength in the sheet plane. Three-dimensional modeling allowed us to study the distribution of normal stresses acting across the thickness of the workpiece. At the radii of curvature of the punch and the bottom of the workpiece, compressive stresses act, in the flange and walls - tensile stresses. It was established that an increase in the strength over the thickness of the workpiece in the form of an increase in the elastic modulus of the first kind made it possible to reduce the deformation of the anisotropic workpiece in a dangerous section. To increase the degree of deformation during drawing in one transition, it is necessary to choose a metal with enhanced strength indicators for thickness or to carry out preliminary preparation of sheet metal before shaping. This will make it possible to reduce the thickness of the workpiece without losing the strength of the final product and, thereby, reduce the metal consumption of the assembly unit.