Strength and stability analysis of deep sea drilling risers

In order to analyze the influence of vortex-induced vibration on the strength and stability of marine drilling risers, a simplified analytical model was established and a method for calculating vortex-induced dynamic response was developed. A case study indicated that at primary resonance, first-order dynamic displacement response is greater than higher-order mode responses, but the influence of dynamic moment and shearing force of higher-order modes cannot be ignored. The natural frequency of risers decreased sharply with increasing length of the riser, but increased with increasing top tension. Various factors should be considered to avoid vortex-induced vibration in practical application, and the influence of vortex-induced vibration could be estimated by calculating the fatigue lifetime of riser.