THE SLIDING CRACK MODEL OF BRITTLE DEFORMATION - AN INTERNAL VARIABLEAPPROACH

Rice's internal variable theory including a micro-to-macro transition is employed to formulate a micromechanical, two-dimensional damage mod el of brittle deformation in compression. The Sliding crack model is s elected as a basic dissipative mechanism underlying macroscopic inelas tic deformation. Microfluxes and conjugated thermodynamic forces are i dentified and incremental stress-strain relations are derived in loadi ng and unloading. Comparison with the model of Nemat-Nasser and Obata (Nemat-Nasser, S. and Obata, M. (1988) A microcrack model of dilatancy in brittle materials. Journal of Applied Mechanics 55, 24-35, in whic h the sliding crack mechanism was analyzed from a kinematic point of v iew, is presented. An illustrative example is worked out showing the c apability of the present model to predict experimentally observed: res ponse of a compact rock. (C) 1997 Elsevier Science Ltd.