The offshore industry is in constant evolution due to the need to reach increasing water depths for new oil fields exploitation. In this scenario, not only new types of platforms are being designed, but also new types of risers, including new flexible pipes and umbilical cable configurations. The greatest difficulty to generate a new concept for a riser is to determine its viability. Flexible pipes and umbilical cables are complicated to model, due to the interactions between their layers and the large number of possible arrangements.

To predict the mechanical behavior of flexible pipes and umbilical cables, adequate models are necessary. One of the possible approaches is to define macro-elements, which represent a component, instead of classical finite elements. Some basic elements for this model were already described in other works, including a cylinder with orthotropic material properties and a helical element for armor tendon modeling. This work shows variation of a node-to-node contact element, which takes into account the different nature of the displacement description. While the displacements used in the cylindrical element uses Fourier series, the displacements used in the helix are described as usual. The approach is to handle the different situations of contact (normal contact, and tangential contact either on slipping or sliding cases) while taking into account the different terms of the Fourier series. The results obtained in case studies are compared to those of a classical finite element modeling tool, with a good agreement.

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