Simplified model of axial compression failure of marine risers

Abstract

Due to the influence of the geometric complexity and the interlayer contact of composite materials, the numerical calculation of axial compression failure of marine risers is complex and time-consuming.Therefore, a simplified model of axial compression failure of marine risers, in which the 8-layer pipe section is simplified to a 5-layer pipe section, was proposed assuming the equivalent stiffness.The rationality and the practicability of the simplified model was verified through stiffness checking and experimental comparison.The failure response of riser under axial compression was studied based on the simplified model, which improved the convergence of nonlinear analysis and computational efficiency.The results show that, when the wear-resistant layer and the outer protective layer reach the yield strength of the material, the inner and outer tensile armor layers will expand rapidly in radial direction to form a separation gap.The wear-resistant layer and the outer protective layer will be destroyed if they reach the ultimate strength of the material, leading to a maximum separation gap in the inner and outer tensile armor layers and depriving the riser's resistance to axial compression.The simplified model could simulate the axial compression failure of marine risers, providing technical support for the design and installation of marine risers.

Keywords

• marine risers
• equivalent stiffness
• compression failure
• simplified model