A discrete approach for modeling damage and failure in anisotropic cohesive brittle materials

This paper presents a numerical study of damage and failure in anisotropic cohesive brittle materials. An extended rigid block spring method (RBSM) is proposed. The representative elementary volume (REV) of brittle materials is characterized by an anisotropic Voronoi assembly of rigid blocks. The macroscopic mechanical behavior is related to the deformation and failure of interfaces between blocks. The mechanical behavior of each interface is described by its elastic stiffness, tensile strength and shear strength. The local elastic stiffness of interface can be related to the macroscopic elastic properties of material. Two failure processes of interface are considered. The tensile failure occurs when the normal stress reaches the tensile strength. The shear failure is described by a nonlinear criterion in terms of the local normal and shear stresses. The proposed method is applied to a typical clayey rock which exhibits a transversely isotropic behavior. Numerical simulations are presented and compared with experimental data.