Fatigue crack growth calculations for two adjacent surface cracks using combination rules in fitness-for-service codes

Lu, K.; Li, Y.

AIMS Materials Science, 4(2), p.439 - 451, 2017/03

https://doi.org/10.3934/matersci.2017.2.439

If multiple discrete cracks are detected in structural components, the combination rules provided in fitness-for-service (FFS) codes are employed to estimate the remaining lives of the components by fatigue crack growth (FCG) calculations. However, the specific criteria for combination rules prescribed by various FFS codes are different. This paper presents FCG calculations for two adjacent surface cracks in a flat plate using different combination criteria. Three different crack aspect ratios of 0.05, 0.15 and 0.5, and a nominal distance of 5 mm between the two cracks are investigated in the calculations. The results show that the FCG behaviors obtained by various codes are significantly different. In addition, the combination process of the two cracks is found to affect the crack shape development remarkably.