Speaker
Description
The rupture of the tensile armour wire is the most critical failure modes for flexible riser which threatens the structure integrity as its load capacity is significantly reduced. Reassessment of the damaged flexible riser against Ultimate Limit State (ULS) and Fatigue Limit State (FLS) need to be performed. This paper investigates the stress concentration factor at tensile armour wires under combined bending and tension load when flexible riser is exposed to corrosion damages in the outer layer of tensile armour wires. The numerical analyses are performed for intact and damaged scenario with 2, 4 and 6 broken tensile armour wires at outer layer for tensile load or bending load. The results from intact conditions are compared with analytical solutions and they show good agreement with each other. The contribution to the different stress components is evaluated for the tensile and bending load conditions respectively and it found that the bending load has most significant contribution to the increase of the dynamic stress. The increase in mean and dynamic stresses are also investigated for the combined tension and bending loads to verify the proposed methodology. As the one of most important parameters the influence of friction coefficients on the stress concentration factor is also studied. The results provide the basis for the life extension analysis of the damaged flexible riser and its application in the design of flexible riser could also significantly enhance the reliability of the design.
| Conference Topic Areas | Track4: Structural Safety, Integrity Management and Life Extension of Structures |
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