A model for propagation and concentration of microcracks

We present a model for mode I propagation and concentration of microcracks in brittle solids driven by remote stresses or volumetric changes, e, g., d ue to thermal contraction or desiccation. Using a crack density integral, w e obtain an effective elastic tensor; the dynamics of the crack density int egral is described by an additional differential equation assuming subcriti cal microcrack growth. Numerical simulations allow the investigation of the physical background of pattern evolution and provide some hints that the p attern formed by the concentration of microcracks may have a significant in fluence on the macroscopic crack pattern which finally occurs.