2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference
Mr. Muntaseer Kainat, University of Alberta
Ms. Diana Abdulhameed, University of Alberta
Dr. Marwan El Rich, University of Alberta
Mr. Michael Martens, TransCanada PipeLines Ltd.
Dr. Samer Adeeb, University of Alberta
Dr. Roger Cheng, University of Alberta
Steel pipe elbow is a common feature in piping systems which is used to change the direction of a straight pipe. The Bourdon effect is the phenomenon of the elbows tending to straighten out when pressurized. Shemirani et al. (2014) studied the influence of the Bourdon effect on the ovalization developed in the elbows for fixed boundary conditions. They showed that there is an increase in the stresses within the elbow; however, this effect is not at all addressed in the Canadian oil and gas pipeline code CSA Z662-11. Kainat et al. (2014) studied how geometric imperfections influence the Bourdon effect in the elbows for fixed boundary conditions. Here we extended the study of the Bourdon effect by focusing on the behavior of pipe elbows using different boundary conditions and neglecting any initial geometric imperfections. Nominal pipe sizes of 12, 36 and 42 inch were selected with constant thickness throughout the pipe. 90º pipe elbow models with two straight pipe attachments have been analyzed using finite element analysis software ABAQUS for different boundary conditions at the ends of the straight pipe attachments. The ends have been allowed to expand in the radial direction upon pressurization to prevent stress concentrations. Under normal operating pressure for (80% SMYS) hoop stress; the Bourdon effect, von Mises stresses and reaction force in the pipe elbows were investigated. From the analysis results, the effect of the boundary conditions on the mechanical response of the elbow is investigated.