An analysis of the Effect of Polymer Intrusion at Interlocked Carcass Gaps

Lucas Lisbôa Vignoli¹; Paulo Pedro Kenedi²

¹ Puc_Rio; ² CEFET/RJ

doi:10.20906/CPS/COB-2015-0250

Resumo

The interlocked carcasses are lightweight and have high radial resistance with negligible bend and axial stiffness, which are particularly important for multilayered tubular structures. They are used in flexible pipes and umbilical cables. At both applications, a polymeric layer must be extruded upon the carcass, to act as fluid barrier. The carcass profile has irregular shape, usually with a profile similar to an "S", and an inevitable consequence of the fabrication process the polymer can penetrate the emptiness between gaps profile. Usually this fact is not considered at the design stage. This paper addresses some possible issues caused by this model simplification. To evaluate the polymer effect, a finite element approach is implemented considering the main load condition, the hydrostatic external pressure, that the carcasses are submitted during the operational phase. A simple analytical model is also presented, which does not take this polymer effect into account, to evidence the non-conservative aspect of this assumption.

Palavras-chave: Interlocked carcass; Finite Elemet; Stress Analysis