Based on the energy principle, a method for fracture mechanics applicable to elastic-plastic fracture of various kinds of ceramic materials was proposed. The elastic-plastic fracture energy associated with crack extension was separated quantitatively into the elastic energy release rate Gc for the cracks faces and the plastic energy dissipation φp. The importance of the plastic energy dissipation in the resistance for crack extension in the elastic-plastic fracture of an artificial isotropic graphite was elucidated by using the proposed energy method.
