ELASTIC INTERACTIONS OF A FATIGUE-CRACK WITH A MICRODEFECT BY THE MIXED BOUNDARY INTEGRAL-EQUATION METHOD

In this paper, the mixed boundary integral equation method is develope d to study the elastic interactions of a fatigue crack and a micro-def ect such as a void, a rigid inclusion or a transformation inclusion. T he method of pseudo-tractions is employed to study the effect of a tra nsformation inclusion. An enriched element which incorporates the mixe d-mode stress intensity factors is applied to characterize the singula rity at a moving crack tip. In order to evaluate the accuracy of the n umerical procedure, the analysis of a crack emanating from a circular hole in a finite plate is performed and the results are compared with the available numerical solution. The effects of various micro-defects on the crack path and fatigue life are investigated. The results agre e with the experimental observations.