Properties of unbonded flexible pipe under axial force

Flexible pipes, which can be divided into bonded and unbonded types, have been used for years in the oil industry. An unbonded structure presents a large interest in offshore production as they allow to realize simple liaison between the seafloor and the surface. In the present paper, an unbonded flexible pipe under axial force has been analyzed by finite element (FE) method in which eight layers of the unbonded flexible pipe have established. Solid and shell elements are used to simulate the layers. In the FE model, all layers are modeled separately with contact and friction interfaces between each layer. The numerical results are compared to the literature's results, which shows very good agreement with numerical and other existing results, have validated the use of the given model. It might provide practical and technical support for the application of flexible steel pipes.