Location

London

Event Website

http://www.csce2016.ca/

Description

Pipe bends are frequently used to change the direction of a pipeline. The location of bends in a pipeline system is often the location that shows high stress levels. The increase in stress is due to the high flexibility of the bend resulting from the ability of the cross-section to ovalize when subjected to bending or internal pressure. Moreover, the surface geometric characteristics of bends may lead to a host of unbalanced thrust forces caused by the internal pressure. The internal pressure results in an outward resultant force that tends to straighten out the bend causing an increase in the deformations and stress levels. This phenomenon is known as "The Bourdon effect". If this outward force is not taken into consideration, unanticipated deformations and high stress levels could occur that may not be accounted for in traditional stress analysis. A better understanding of the influence of the Bourdon effect on the elbow design parameters is required. The increase in stress levels is considered using stress intensification factors presented in current codes. In this paper, the stress intensification factors presented in the current code were revisited for the case of different loading conditions and compared to FEA results. The study showed that the direction of applied bending moment on the bend has a significant effect on the distribution and magnitude of the stresses depending on the level of applied internal pressure.


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Jun 1st, 12:00 AM Jun 4th, 12:00 AM

STR-872: THE INFLUENCE OF THE INTERNAL PRESSURE AND IN-PLANE BENDING ON PIPE ELBOWS

London

Pipe bends are frequently used to change the direction of a pipeline. The location of bends in a pipeline system is often the location that shows high stress levels. The increase in stress is due to the high flexibility of the bend resulting from the ability of the cross-section to ovalize when subjected to bending or internal pressure. Moreover, the surface geometric characteristics of bends may lead to a host of unbalanced thrust forces caused by the internal pressure. The internal pressure results in an outward resultant force that tends to straighten out the bend causing an increase in the deformations and stress levels. This phenomenon is known as "The Bourdon effect". If this outward force is not taken into consideration, unanticipated deformations and high stress levels could occur that may not be accounted for in traditional stress analysis. A better understanding of the influence of the Bourdon effect on the elbow design parameters is required. The increase in stress levels is considered using stress intensification factors presented in current codes. In this paper, the stress intensification factors presented in the current code were revisited for the case of different loading conditions and compared to FEA results. The study showed that the direction of applied bending moment on the bend has a significant effect on the distribution and magnitude of the stresses depending on the level of applied internal pressure.

http://ir.lib.uwo.ca/csce2016/London/Structural/43