An Unbonded Flexible Pipe Finite Element Model

Gabriel Gonzalez¹; José Renato Sousa¹; Luis Volnei Sagrilo¹

¹ Universidade Federal do Rio de Janeiro

doi:10.20906/CPS/CILAMCE2015-0373

Resumo

Unbonded flexible pipes are multi-layered structures with their typical cross-section composed by a combination of steel armoring layers (inner carcass, tensile and pressure armors) and polymeric conduits and tapes. This paper presents a finite element model, entirely developed in ABAQUS® environment, fully capable of calculating stresses and strains in those several layers when subjected to different types of loads. The finite element model employs four nodes reduced integration shell elements. The inner layers, located bellow the first tensile armor, are condensed into a unique cylinder with its distinct properties well assured. The same assumption is applied to the layers placed above the second tensile armor. Moreover, rebar elements were considered for the carcass and pressure armor modeling. As for the tensile armors, each steel tendon is modeled individually by shell elements. The interactions between tensile armors tendons and between the tensile armors and the adjacent layers are handled with tangential and normal contact formulations. As a case study, a 2.5" unbonded flexible pipe is considered under pure tension. The results obtained are compared to an existing analytical model as well as from previously published experimental data. All results agreed quite well.

Palavras-chave: Finite Element Method; Structural Analysis ; Unbonded Flexible Pipe