Energy-based model of compressive splitting in heterogeneous brittle solids

Confined heterogeneous brittle solids loaded under far-field uniaxial compression are often observed to split along the loading axis. We develop a theory which accords this phenomenon an energetic interpretation : the solid splits because in so doing it reduces its total energy, defined as the sum of bulk strain energy and surface energy. The heterogeneous microstructure gives rise to a complex stress distribution in the intact solid. We show that the change in energy due to the release of the microstructural stresses may exceed the cost in fracture energy. Critical conditions for splitting are formulated for polycrystalline solids as a function of readily measurable material properties and applied stresses. The predictions of the theory are found to be in remarkably good agreement with experimental observations in ceramics and rocks.