A theoretical investigation of the fracture energy of heterogeneous brittle materials

It is shown that the fracture surface energy of heterogeneous brittle materials (polycrystals, composites, ceramics, rocks) depends on their microstructural characteristics, namely the fractal properties of the network of microcracks. A quantitative approach for the calculation of fracture energy from microcrack network fractal parameters is suggested. Very high experimental values of fracture energy for heterogeneous brittle materials can be easily explained in the framework of the fractal model.