Issue 35

R. Citarella, Frattura ed Integrità Strutturale, 35 (2015) 523-533; DOI: 10.3221/IGF-ESIS.35.58 525 p s L3  L1  p  s  L  L2  Lc  e i  d  e b  L 555 L1 299,5 L2 299,5 L3 440 Lc 44 ei 3,2 eb 1,6 Number of rows 2 Number of columns 20 p 22 s 22 d 4,8 Figure 1 : Specimen geometry. x y Figure 2 : Intermediate crack scenarios up to 393000 fatigue cycles. By means of a convergence study, it has been assessed that only in cracked holes and in holes nearby cracks it is necessary to explicitly model pins (rivets), whereas the remaining holes can be simply constrained against y-translation, as already mentioned. The secondary bending (Fig. 4) is not considered, but the level of approximation introduced is judged acceptable for such kind of problems due to relevant plate flexural weakening caused by long cracks on the verge to become unstable (see [6] for a discussion on this topic).