Abstract
The dynamic fracture process of a material containing an array of cracks is studied. By symmetry a unit crack body is analyzed, with the material separation behavior described by a linear cohesive law. Exact solutions of the problem are obtained by using Laplace transform, rendering the theoretical expressions for the crack and the boundary stresses, and the energy flux into the crack body during fracture. For a prescribed strainrate, the energy flux is evaluated for different crack spacing. It is found that there exists a preferred crack spacing corresponding to the minimum energy flux, and the value of this spacing is a reasonable estimate of the average fragment size in a natural brittle fragmentation process.