An adhesively bonded asymmetrical weak zone was proposed as a model for studying the problem of interaction between crack-like defects in an elastic medium. The opening of the weak zone was prescribed by a 2-parameter basis function. That is, by a special dislocation which automatically accounted for the asymmetry and other physical features of the stress–strain field near to the tips of the weak zone. The adhesive forces corresponding to the prescribed opening were then calculated from a solution of the particular problem. The model was demonstrated by applying it to the problem of a long interface crack, subjected to wedge-opening forces, which was separated from a short co-linear interface weak zone by a small strong unbroken microstructural feature, such as a small obstacle. Two key questions were whether the weak zone became the nucleus of a cohesive crack on its own, without linking with the pre-existing long crack, and when did it force rupture of the obstacle and coalesce with the long crack.

Dislocation Model of an Asymmetric Weak Zone for Problems of Interaction Between Crack-Like Defects. I.V.Simonov, B.L.Karihaloo: Philosophical Magazine, 2005, 85[17], 1847-64