Formulation of a 3-D numerical model of brittle behaviour

摘要: SUMMARY A 3-D numerical model of brittle behaviour is proposed where matter discretized in individual elements. These particles are linked by tensile interaction forces generating cohesive media. spring-like linear and elastic when a small stretching effect applied decrease linearly to zero if the exceeds rupture threshold. Hence, for infinitesimal strains, medium has an response waves can propagate. For finite deformations, links break, thus simulating microcracks, eventually evolve into macroscopic fracturing process. If stacked according face-centred cubic lattice structure interact with first second nearest neighbours, then isotropic elastic. To determine strength properties this model, uniaxial compressional tests run. On basis Mohr circle analysis, fracture criterion reference agrees Mohr-Coulomb criterion. However, evolution fractures do not follow direction predicted The volumetric strains comparable laboratory observations on rock samples under compression. Dilatancy begins at about half failure stress microcracking propagates pervasively throughout sample prior failure. angles dilatancy, vertical. With increase dilatancy angle vertical disappear shear appear 45° from main axis strain. Ultimately, increasing these zones migrate centre sample. Fractures aligned preferentially along axes symmetry FCC structure. This emphasized use central low residual friction.