Stress intensity factors for corner cracks emanating from fastener holes under tension

In this paper, previous work associated with the stress intensity factor for corner cracks at fastener holes in finite thickness plates is briefly reviewed. The stress intensity factors for two symmetric quarter-elliptical corner cracks subjected to remote tension are evaluated by using both the quarter-point displacement and J-integral methods based on three-dimensional finite element analyses. The geometry ratios analyzed cover a wide range, i.e. depth ratio a/t: 0.2-0.95, aspect ratio a/c: 0.2-5, and hole radius ratio r/t: 0.5-3. Analysis of the J-integral path independence and mutual comparison of the stress intensity factor results between the two methods demonstrate that the present results are of good numerical accuracy. Deviation of the present results from some other solutions found in the literature is also revealed, particularly from Newman and Raju's equations. It is shown that the difference among these results obtained by the different methods is generally within a reasonable bound of error, but Newman and Raju's equations systematically underestimate (up to 15%) the stress intensity factor for cracks of depth ratio larger than 0.8. (C) 1999 Elsevier Science Ltd. All rights reserved.