FRACTURE IN A HETEROGENEOUS MEDIUM - A NETWORK APPROACH

Fracture in a heterogeneous medium is simulated by a network model. Heterogeneity is introduced by randomly distributing an initial population of cracks on a triangular network of bonds. Each ruptured bond represents a crack. External stresses are applied onto the network and the evolution of the crack population is analysed when the stresses are increased. A crack will propagate to an intact bond if the critical crack extension force is reached. This propagation leads to the coalescence of bonds: crack clusters are formed. When their shapes are complex we approximate them by simpler ones to compute a crack extension force. Crack interactions are introduced by adding for a given bond the contributions of all adjacent clusters. By using this kind of approach combining fracture mechanics and network modelling, we are able to simulate the rupture of a rock specimen under compression/traction or shear stresses and to give some characteristics of the macroscopic fracture.