Crack propagation in a brittle elastic material with defects

A two-dimensional asymptotic solution is presented for determination of the trajectory of a crack propagating in a brittle-elastic, isotropic medium c ontaining small defects. Brittleness of the material is characterized by th e assumption of the pure Mode I propagation criterion, The defects are desc ribed by Polya-Szego matrices, and examples for small elliptical cavities a nd circular inclusions are given. The results of the asymptotic analysis, w hich agree well with existing numerical solutions, give qualitative descrip tion of crack trajectories observed in brittle materials with defects, such as porous ceramics.