Modelo de partículas 3D para o estudo da fratura em rocha com base em diagramas de voronoi da estrutura granular

Particle models, by taking into account the material grain structure, explicitly consider the material randomness and have been successfully applied to rock fracture studies. In this work a 3D particle model based on the Laguerre-Voronoi diagrams of the grain structure is presented. The proposed model takes into account the effect of the polyhedral shape but still keeps the simplicity and the reduced computational costs associated with spherical particle models. A multiple contact model is presented in which the contact surface is based on the common facet of the associated particle Laguerre-Voronois diagrams. The particle model is validated against known experimental data on a granite rock (triaxial, uniaxial and Brazilian tests). Several parametric studies are presented showing the influence of the elastic and strength particle parameters on both the macroscopic elastic and strength properties. A reference is also made to the relevance of adopting a bilinear tensile/shear softening contact model in order to obtain coherent ultimate tensile values in direct tensile tests and in Brazilian tests.