Issue 31

A.R. Maligno et alii, Frattura ed Integrità Strutturale, 31 (2015) 97-119; DOI: 10.3221/IGF-ESIS.31.08 108 Figure 14 : Location of initial cracks (half model) Numerical Results: Stage 1 The final dimensions and shapes of simulated cracks in the conductor and in the casing, corresponding to the end of Stage 1, are shown in Fig. 15. (a) (b) Figure 15 : Simulated final crack shape at the end of Stage 1 analysis: (a) conductor; (b) casing. The circle show the initial crack configuration. It can be noticed that a negligible crack growth took place in the casing (Fig. 15b). The results, in terms of a - n and K - a relationships , for both the inner-surface crack-front node and the through-the-thickness crack-front node, at the end of Stage 1 (when the conductor pipes crack was about to break through the thickness) are presented in Figs. 16-18. The respective number of fatigue cycles n was 2.6E+06. Figure 16 : a vs . N for thickness node (conductor).