by Katerina Pappa
Diploma Thesis, July 2005
Using a simple two dimensional model, the buckling strength of thick-walled cylindrical pipes under external pressure is investigated. The pipes are candidates for use in deep water applications (more than 1000 meters of water depth) and are manufactured through the UOE procedure, where the steel plate is first bent into a U shape, then further bent into a circular shape and welded (O-ing) and, finally, expanded to reach the final shape (E-ing). This manufacturing procedure results in the development of significant residual stresses that may cause buckling at a stage earlier than the one assumed in various relevant codes and specifications.
The present work is aimed at the development of a finite element model with program ABAQUS that employs elastic-plastic large-strain elements, and simulates the manufacturing procedure and models the buckling behaviour of such pipes under external pressure.