A ZENER-STROH CRACK NEAR AN INTERFACE

A micro crack can be initiated by coalescing dislocations piled up alo ng a slip plane. This mechanism was firstly proposed by Zener and late r on analyzed by Stroh. The micro crack is thus called Zener-Stroh cra ck, which is a counterpart of the well-known Griffith crack in linear elastic fracture mechanics. In the present paper, we consider a Zener- Stroh crack initiated near a bi-material interface. Due to image force acted on the dislocations, a Griffith crack mechanism is introduced e ven where the crack is purely loaded by net dislocations. It is seen t hat the stress intensity factor, which consists of a Zener-Stroh compo nent and a Griffith component, and the critical crack length are stron gly affected by the presence of the interface. (C) 1997 Elsevier Scien ce Ltd.