A Three-Dimensional FE Approach for the Stress Analysis of Tensile Armors Inside End Fittings

Abstract

In this work, a solid three-dimensional finite element (FE) approach is proposed to investigate the stress distribution along the tensile armors of flexible pipes inside their end fittings (EFs). This approach employs two different models. The first model consists of a single tensile armor, which is meshed with solid FEs, and a rigid surface that represents the EF. A toroidal template is also considered and the EF mounting process is simulated. In the second model, the deformed armor and the stress state from the first model are considered and the voids between the armor and the EF are filled with resin, which is also modeled with solid FEs. Geometric and material nonlinearities are addressed and the interaction between the different components are ensured with contact elements. A case study is conducted to observe the stress distribution along the tensile armor considering typical operational loads. The results obtained are compared to those calculated with a previously proposed analytical model showing good agreement, but also evidencing the need to adequately simulate the EF mounting process and the pre-operational tests. Moreover, intense stress concentrations at the entrance of the EF are observed thus indicating that this region can be critical in fatigue analyses.