Finite element modeling of burst failure in unbonded flexible risers

• This paper presents finite element modeling of burst failure in flexible risers.
• The methodology contributes to the design of the pressure armor for flexible riser.
• The mathematical formulations were used to validate the finite element modeling of burst in flexible risers.

Flexible risers can be subjected to high levels of internal pressure caused by hydrocarbon pressure gradients coming from the reservoir. Therefore, flexible risers can failure by burst of the riser, caused by a pressure armor failure, which were designed to resist the internal pressure or radial loads. This paper presents a burst analysis methodology by performing analytical, 2D and 3D finite element modeling of a section of a flexible riser. In order to obtain reliable results, it was necessary to consider in the finite element modeling both, geometric and physical nonlinearities due to the contact conditions between the two different layers of the riser considered in burst analysis. The results were compared with various existing analytical models with good correlation, and also showed the importance to develop finite element models for a proper burst analysis of flexible risers. The methodology was applied to a flexible riser manufactured with pressure armor with a “Z” profile.