Issue 51

C. Anselmi et alii, Frattura ed Integrità Strutturale, 51 (2020) 486-503; DOI: 10.3221/IGF-ESIS.51.37 498 Figure 15 : Collapse mechanism for case 7 (failure at ribs / Lf=2 / Nh=0 / sT=1.5 / multiplier α=3.168) Feature (b): hoops in the case of possible failure at the ribs; For the same case 7 shown in Fig.15 with possible failure at ribs, if you introduce 2 hoops the α value increases to about seven and half (case 8 shown in Fig.16). Figure 16 : Collapse mechanism for case 8 (failure at ribs / Lf=2 / Nh=400 / sT=1.5 / multiplier α=7.624) Feature (d): drum width. Finally, if instead of introducing the hoops (Fig.16), the thickness of the drum is increased from 1.5 to 2.5 meters, the α value increases from about 3 (case 7 shown in Fig.15) to about 13 (case 11 shown in Fig.17).