The failure of brittle solids containing small cracks under compressive stress states

Abstract

Brittle materials (ceramics, rocks and ice are examples) may contain a distribution of small, grain-sized, cracks. When loaded in compression, these cracks propagate stably until they interact to give final failure. A model is developed for the growth and interaction of cracks in brittle solids under compressive stress states. A critical stress is required to initiate crack growth: it depends on the initial crack length and orientation, on the coefficient of friction and on the stress state. The cracks then grow in a stable way until they start to interact; interaction increases the stress intensity driving crack growth and leads to instability and final failure. This chain of events is modelled, and the framework of a theory of damage mechanics is suggested.