No abstract

No abstract

The equivalent initial flaw size (EIFS) concept was developed nearly 30 years ago in an attempt to account for the initial quality, both manufacturing and material properties, of a structural detail prone to fatigue cracking. Widespread use of this concept has been limited due to the large amount of test data required to develop a reliable EIFS distribution. In this effort, an EIFS distribution was determined for four types of flat, production like transport aircraft fuselage skin joints loaded by remote tension. Two crack growth prediction codes, AFGROW and FASTRAN, were used to not only develop the EIFS but also to compare the crack growth algorithms in each code. The EIFS calculations are prone to compounding errors in the crack growth analysis due to the changing stress intensity factor solutions and stress fields as the crack gets longer. Thus, only including EIFS calculations for mechanically small cracks, crack lengths less than 1.27 mm, results in a mean EIFS of 18.0 μm with a standard deviation of 3.78 μm.

Non-dimensional geometric correction factor, ß, data for stress intensity factor, K, calculations are generated through finite element analyses and collected from the literature for axially loaded single-edge cracked plates with rotationally free and constrained loaded edges typically used in fatigue crack growth experiments. The solutions are valid for crack length-to-width ratio, a/W, in the range of 0.01 ≤ a/W ≤ 0.975 and plate height-to-width ratio, H/W, in the range of 0.8 ≤ H/W ≤ 10.0. Comparisons are made between the literature reported data and the present effort's results with generally satisfactory correlation. However, differences as large as 12.7% exist for short cracks in small H/W valued plates. ν -Poisson ratio σ -average far-field axial stress © 2015. This manuscript version is made available under the Elsevier user license