Yield Stress of Randomly Perforated Sheets and Anisotropic Yield Function.

Abstract

The influence of the distribution of voids on macroscopic mechanical properties is an important problem in plastic deformation of damaged materials. Since the distribution of voids in actual damaged materials is heterogeneous, we have to evaluate the heterogeneous distribution of voids quantitatively. We propose a new method using the voronoi tessellation and the stereology to evaluate the heterogeneous distribution of voids in this paper. In order to verify the availability of the new method, perforated sheets with randomly distributed holes are set up as plane models of damaged materials and are examined under uniaxial tension. Mechanical properties of perforated sheets are estimated by anisotropic yield function and the relationship between distiribution of holes and macroscopic yield stress is investigated quantitatively. It is shown that the method is valid for evaluating the heterogeneous distribution of holes.