Interaction of a crack with certain microcrack arrays

Interaction of a crack with microcracks (modelling “damage”) can significantly alter the stress concentration at the crack tip. Certain important effects of interaction—shielding effect (“toughening by microcracking”), amplification effect, influence of the orientations of microcracking and irregularities in its patterns, change of the character of interaction (shielding to amplification and vice versa) with change of the mode of loading, etc.—are demonstrated on several microcrack systems. It appears that these relatively simple systems exhibit the essential features of the crack-damage interactions. Consideration is based on the method of analysis of elastic solids with many cracks proposed recently [Kachanov, Int. J. Fracture 28, R11–R19 (1985); Kachanov, Int. J. Solids Structures (in press)] and briefly presented here.