The first seminar of the semester will be this Friday! MASc CandidateMajid Tanbakuei Kashani will be giving a talk on “Effect of Forming Process on the Deformational Behaviour of Steel Pipes”. The seminar abstract is below.
Date: Friday September 16th
Room: SITE J0106
Buried pipeline networks play a vital role in transportation of oil and natural gas from centers of productions to centers of consumptions. A common manufacturing technique for such pipes is the UOE process, where a flat plate is first formed into a U shape, then in an O shape, welded at the seam, and Expanded before being shipped on site. The UOE forming process induces residual strains in the pipe.
When buried pipelines cross the regions of discontinuous permafrost, they undergo differential frost heaving, inducing significant bending deformations, which potentially induce local buckling in the pipe wall. To control local buckling, design standards impose threshold limits on buckling strains. Such threshold values are primarily based on costly full-scale experimental results. Past nonlinear finite element analysis attempts aiming at determining the threshold buckling strains have neglected the presence of residual stresses induced by UOE forming and were thus found to grossly overestimate the buckling strains compared to those based experiments.
Within the above context, the present study focuses on developing a numeric technique to predict the residual stresses induced in UOE forming, and incorporating the residual stresses in 3D nonlinear FEA modeling to predict improved buckling strain limits. Comparisons against conventional analysis techniques that omit residual stresses reveal the importance of incorporating residual stresses when quantifying buckling strains.