On Bending Capacities of 6” and 12” Spool Bends in Deep Water

This paper presents a bending capacity study to 6” MEG and 12” production flowline spool bends. Various design criteria for assessing the bending capacity of spool bend have been investigated. Based on detailed disucssions, a combined criterion is concluded finally, in which sufficient safety margin and as well as the acceptable ovality are both considered. In this study, the spool bending capacity assessment comprises of three parts. Firstly, the local nonlinear finite element model of the spool bend is analysed by the implicit solver cooperated in LS-DYNA. The bend capacities are established based on the combined criterion concluded in this paper. Secondly, the global finite element model of the whole spools are analysed by ANSYS 13. The global model is only considered in linear regime. All practical loading cases during the spool’s service time are included. The actual loading for the spool bends under different loading cases are summarized. Finally, the results from global and local models are compared with each other. The bending capacity check is done by making sure that the actual loading of spool bend from the global model is no bigger than the bend capacities obtained from the local numerical model. Quite a few numerical simulations have been carried out. Conclusion remarks are summarized at the end of present paper.