The role of cohesive properties on intergranular crack propagation in brittle polycrystals

We analyze intergranular brittle cracking of polycrystalline aggregates by means of a generalized finite element method for polycrystals with cohesive grain boundaries and linear elastic grains. Many random realizations of a polycrystalline topology are considered and it is shown that the resulting crack paths are insensitive to key cohesive law parameters such as maximum cohesive strength and critical fracture energy. Normal and tangential contributions to the dissipated energy are thoroughly investigated with respect to mesh refinement, cohesive law parameters and randomness of the underlying polycrystalline microstructure.