  We consider the quasi-static propagation of a Mode III crack along the
interface in a bimaterial plane containing a finite array of small line defects
(microcracks and rigid line inclusions). The microdefects are arranged to form
a channel around the interface that can facilitate (or prevent) the crack
propagation. The two dissimilar elastic materials are assumed to be weakly
bonded, so that there is no kinking of the main crack from the straight path.
On the basis of asymptotic formulae obtained by the authors, the propagation is
analysed as a perturbation problem and the incremental crack advance is
analytically derived at each position of the crack tip along the interface
relative to the position of the defects. Numerical examples are provided
showing potential applications of the proposed approach in the analysis of
failure of composite materials. Extension to the case of infinite number of
defects is discussed.
