A corrosion rate and depth time-varying model for X70 steel was obtained by simulating corrosion tests in a deep-sea environment using standard hanging strips.By employing numerical simulations,the fatigue curve for X70 steel with corrosion effects was derived.Next,an integral model incorporating the platform-SCR-soil interaction was developed to analyze the dynamic response of the SCR under environmental loading,corrosion,and internal flow effects for different corrosion durations.Finally,the fatigue life of the SCR with different corrosion durations was analyzed based on the Miner linear damage accumulation criterion.The research findings indicate that the fatigue life of the SCR significantly decreases with increasing corrosion duration.For a corrosion duration of 5 years and internal flow velocities of 2 m/s and 5 m/s,the fatigue life of node at the touchdown point of the SCR was found to be 437.31 years and 89.00 years,respectively.The fa-tigue life at an internal flow velocity of 5 m/s was only 20.36％of the fatigue life at an internal flow velocity of 2 m/s.However,in the absence of corrosion,the fatigue life at internal flow velocities of 2 m/s and 5 m/s was considerably high-er,reaching 3.72×109 years and 1.41×107 years,respectively.Therefore,to ensure the safe operation of SCRs,effective corrosion prevention measures should be implemented,and the internal flow velocity should be controlled within a safe range.
steel catenary risersfatigue performance of corrosiondeep-sea environmentX70 steelfatigue curve with corrosion
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