In recent years, a model based on the Voronoi tessellation and the random electrical networks (EN) has been developed to simulate the influence of the microstructure on the electrical properties of polycrystalline ionic conductor composites and encouraging results have been obtained. By the same approach, the elastic modulus of yttria-stabilized cubic zirconia (YSZ)/Al2O3 has been tentatively simulated exploiting the analogy between the electrical and mechanical dynamic responses. A random network constituted of discrete elastic elements (springs) was used to sketch the mechanical behaviour of these polycrystalline composites. Preliminary results and remarks are presented and discussed.