Offshore Installation of Welded Pipe: Local Buckling Evaluation

Up to the present, most of the pipes used in offshore applications installed with methods introducing plastic deformation have been seamless pipes; however, welded pipes can also be used. Welded pipes offers benefits over seamless pipe in terms of improved lead times, lower project costs, tighter dimensional tolerance and good control of mechanical properties and chemistry resulting in excellent weldability. During installation of welded pipes, failure by fracture, plastic collapse and local buckling may occur. In this work, the occurrence of the local buckling phenomenon, produced during the installation method, was evaluated. Numerical models were developed to study the effect of materials and geometrical parameters on the local bucking of pipes subjected to bending. Specifically, the loads and strains at which the plastic instability occurs were determined for each particular condition. In addition, the influence of longitudinal and girth welds on the local bucking occurrence was assessed.