ABSTRACT
Any machine component, a dam, an aeroplane or a structure during fabrication stage contains not a single crack, but a multitude of cracks. The interaction between cracks may result in an increase (amplification) or decrease (shielding) of the stress intensity factor at the crack tip depending on the positioning of the second or other cracks with respect to the main crack. In this chapter the interaction between line or three-dimensional cracks are critically examined. The first few sections are devoted to study interaction between cracks or cracks parallelly stationed with the main crack. Various integral equation schemes used by various workers are discussed. Major parts of three-dimensional interaction problems discuss parallel or coplanar circular cracks particularly by the method of Kachanov and his associates. Also discussed is Fabricant’s method of exact inversion for normal loading. The last section includes a discussion of the interaction between elliptic cracks as well as interaction between penny-shaped cracks and elliptic cracks by the perturbation technique of Roy and his associates. The Chapter ends with discussion of results of various authors. Both amplification as well as shielding phenomena are observed. While the amplification may hasten the destruction, the shielding assists in arrest of the crack growth.
