NUMERICAL AND THEORETICAL STUDY OF COALESCENCE OF CAVITIES IN PERIODICALLY VOIDED SOLIDS

摘要

This paper is concerned with the coalescence of cavities in von Mises materials containing a periodic distribution of identical cavities and subjected to tensile axisymmetric loadings. It compares the results of some finite element simulations of the behavior of unit cells analogous to, and extending, those of Koplik and Needleman, with those derived from simplified analytic models. One major feature of these models is that they account for the nonuniform and anisotropic distribution of cavities induced by the deformation, by schematizing a unit cell as the union of two zones, a sound one and a highly porous one, the mechanical fields being considered as homogeneous in the latter. These zones are planar layers and coaxial cylinders for predominant axial and lateral stresses respectively. The material behavior in the porous zone is described with the aid of the authors' recent extension, accounting for void shape effects, of Gurson's well-known model. The agreement found between theoretical and numerical results is quite good.