Issue 31

A.R. Maligno et alii, Frattura ed Integrità Strutturale, 31 (2015) 97-119; DOI: 10.3221/IGF-ESIS.31.08 116 shown in Scenario 3, this crack propagated circumferentially in the conductor until it stabilised thanks to the compressive stress state established in the remaining ligament of the pipe due to the shifting neutral axis. At that stage, the inner-wall crack in the casing pipe started growing until it became a through crack, as shown in Scenario 5. Scenario Scenario description Scenario presentation 1 Semi-circular crack only in conductor pipe 2 Semi-circular crack only in casing pipe 3 Through-the-thickness crack propagating in conductor pipe and semi-circular crack in casing pipe 4 Crack propagation only in casing pipe. Conductor is considered fully failed and not bearing any load 5 Crack propagating only in casing pipe. Crack in conductor is not growing due to compressive stress Fractured region Ligament Table 10 : Studied scenarios.