The stress intensity factor Green’s function for a crack interacting with a dislocation S. Teyar 1 and M. Chabaat 2 1 Doctorate, Built Env. Res. Lab., Civil Engineering. Faculty, U.S.T.H.B., B.P. 32 El Alia, Bab Ezzouar, 16111 Algiers, Algeria. teyars@yahoo.fr 2 Professor Built Env. Res. Lab., Civil Engineering Faculty, U.S.T.H.B., B.P. 32 El Alia, Bab Ezzouar, 16111 Algiers, Algeria. mchabaat2002@yahoo.com or mchabaat@usthb.dz Keywords: Crack, microcrack, dislocation, Green’s function, crack amplification, crack shielding, Stress intensity factor. This paper presents the results of the analysis of Green's functions for the problem of interaction between a crack and a surrounding dislocation. It consists in the determination of Green's functions based on the formalism of the complex potentials of Muskhelishvili. On the basis of this latest, Green’s functions are constructed for the Stress Intensity Factor (SIF) in Mode I and Mode II due to the unit dipole force applied to the main crack surfaces in the presence of a dislocation in front of the crack tip. Various stress fields have been obtained taking into consideration interactions between the crack and the microcrack for various configurations such as the orientation as well as the position of the microcrack with respect of the main crack. The effect of amplification and shielding on the resulting stress field is shown, through a study of mode I and mode II SIF. Obtained results are compared and agreed with those of other researchers. Introduction It is well known that in many brittle materials, crack propagation is accompanied by the formation of a damage surrounding the crack tip. This damage develops in a nearby tip-zone called also Fracture Process Zone (FPZ). This latest can reveal itself as the nucleation of many microcracks around the tip of a propagating crack 1, 2. These microcracks can have a significant influence on the propagation of the main crack. They can either cause crack amplification or crack shielding. Crack shielding reduces stress intensity factors of the main crack while crack amplification increases those values. These effects have been investigated by several researchers using exact analytical methods for some particular cases [3], and with analytical approximations under certain assumptions [4, 5]. Because this damage can constitute an important toughening mechanism, problems dealing with crack microcracks interactions have received considerable research attention since they were introduced to fracture mechanics. As a result, a wide body of literature, on this topic, exists 6. Solutions obtained are mostly based on the complex variable technique 7, or on numerical procedures 8, or asymptotic estimates for remotely located cracks 9. Those techniques are usually different to a degree, but the basic principals remain the same. In this paper, interaction between a macrocrack and a microcrack represented by a distribution of dislocations dipole is considered. A stress field distribution induced during these interactions is obtained using Muskhelshvili’s complex variables formalism which relies