Numerical analyses on limit load of X60 pipe elbow in different internal corrosion-damaged positions under combined internal pressure and in-plan bending moment

The objective of this study is to predict the damage occurring in a pipe elbow when exposed to combined internal pressure and in-plane bending moment, considering different defect positions. The damage assessment of the elbow, which includes internal wall defects at various locations on the extrados, was conducted using the Extended Finite Element Method (X-FEM). The analysis demonstrates that the damage experienced by the pipe elbow is primarily influenced by the bending moment and the proximity of the defect to the point of maximal bending moment or the critical elbow zone. Nonlinear variations were observed in collapse and instability loads based on the defect's position within the elbow. The same applies to the weakening factors associated with these two loads.