Analysis of tensile armor layer structural behaviors in flexible pipe

Tensile armor layers of flexible pipe are complex helix structures, whose stress analyses are significant to flexible pipe's fatigue, strength and buckling behaviors. This paper is based on curved beam theory. Equilibrium equations of tensile armor wires in deepwater unbonded flexible pipe were solved with assumptions of loxodromic curve and geodesic curve, based on slender rod theory and elastic constitutive relationship. The curvatures and structural response under axisymmetric load and bend moment were analyzed. A three dimensions beam finite element model and a three dimensions curved beam element model were built by FEM software to compare with the results. The results show that the formulations and codes are reasonable for predicting structural responses of tensile armor wires. This solution provides a fast method to evaluate the stress and curvatures in design of flexible pipe's preliminary design. ©, 2015, China Ship Scientific Research Center. All right reserved.