Ductile damage of a bi-porous saturated material under dynamic loading: constitutive modeling and numerical simulations

Titre du congrès :EMMC-10 Conference "Multi-phases and multi-components materials under dynamic loading' Ville du congrès :Kazimierz Dolny Date du congrès :11/06/2007

This study is devoted to the modeling of ductile damage in highly irradiated uranium dioxide. This polycrystalline material contains two populations of saturated cavities of well separated size. At the smallest scale, the cavities are intragranular and almost spherical. At the largest scale, the cavities are located at the grain boundaries and are almost ellipsoidal. The overall elastic behavior is estimated at each scale by a classical linear homogenization scheme. The effective flow surface and the quasi-static evolution of the micromechanical parameters are estimated with the help of the variational approach of Ponte Castañeda and Suquet (1998) applied to a Gurson-like matrix containing randomly oriented ellipsoidal cavities. The estimate of the effective flow surface is compared to a new upper bound. The coalescence of the ellipsoidal voids is studied by way of numerical simulations where the grains are represented as Voronoï cells and intergranular fracture is modeled with cohesive zone elements.