Finite element analysis of mechanical connectors

Mechanical connectors are often used to facilitate the rapid construction and dismantling of pipelines. BP acquired 6m lengths of sectional pipe with mechanical connectors welded onto each end, which was intended to be used for the construction of a pipeline.

Very little design information was available for the pipe and connectors. Data on dimensions, dimensional tolerances and material properties were collected by direct measurement and testing of the available pipe.

BP asked Jee to perform finite element analysis on the sectional pipe connection.  The purpose of the analysis was to study the mechanism of the connector and to determine the stresses arising from construction and from operation, the capability of the joint to carry tensile and compressive loads, and to verify that a leak-tight seal is achieved over the full range of operating conditions.

Weld geometry was included in the analyses and the effect of defects on the internal welds was determined.  In addition, stress intensity factors for three different crack penetration depths on the welds between the pipeline and the connector component were determined.

Results of finite element analysis were used as part of a process for verification of fitness for service of the joint design and also to provide a level of assurance of the results of full scale tests that were carried out separately.