Numerical analysis of dynamic and fatigue characteristics of deep-sea mining riser considering irregular waves and currents

• Published in: Ocean engineering 2024-11, Vol.311, p.118910, Article 118910
• Main Authors: Li, Yan, Zhou, Xingkun, Dou, Yaning, Zhang, Xiantao, Li, Wenhua
• Format: Article
• Language: English
• Subjects: Fatigue; Irregular waves; Mining riser; Time-domain finite element method; Vibration
• ISSN: 0029-8018
• DOI: 10.1016/j.oceaneng.2024.118910

In deep-sea mining operations, the mining riser is the most fragile and technologically demanding segment of the entire system. It is crucial to investigate the dynamic response and fatigue characteristics of mining risers to elucidate their motion patterns and fatigue mechanisms. In this study, we examine the vibration behavior of the deep-sea mining riser using the time-domain finite element method under various sea conditions and estimate the fatigue life of the mining riser based on the Miner-Palmgren damage rule. Results indicate that the significant wave height and peak period of irregular waves significantly influence the dynamic response characteristics and fatigue damage properties of the riser. The axial displacement, rotation angle, bending moment, effective tension, and von Mises stress of the riser are maximized and minimized at the top and bottom, respectively, whereas the lateral displacement shows the opposite trend. In general, the axial displacement exhibits a more complex pattern than the lateral displacement, and the maximum fatigue damage is predominantly concentrated in the middle and upper sections of the riser. •Dynamic behaviors of a deep-sea mining riser under various sea conditions are investigated.•The axial compared with lateral displacements of the riser demonstrate a more intricate pattern of behavior.•The motion trajectory and frequency of the buffer station of the mining riser are ascertained.•The dynamic stress levels and fatigue distribution along the mining riser affected by the irregular waves are given.