中文摘要：

海底管道悬跨管段在波流联合作用下非常容易发生疲劳破坏。文章在结合所做的一系列试验结果的基础上,建立了管跨在波流联合作用下的涡激振动力学模型。通过模态分析,求得振动方程的固有振型,并以此为基础,综合考虑垂向响应和流向响应对管跨截面处应力的影响以及平均应力存在时对疲劳寿命的影响,运用谱分析理论和疲劳分析理论建立更为合理可靠的海底管线疲劳寿命预测方法。最后通过实例计算,确定平均应力的存在对管跨疲劳寿命的影响程度。

英文摘要：

The Submarine Pipeline Spans are vulnerable to considerable fatigue damage over its design life period due to the dynamic excitations caused by Vortex Induced Vibration（VIV） in waves and current.In this paper,according to the tried experimentation,the model of vortex-induced vibration in wave and current is proposed.Based on inherent modes determined by the equation of motion describing free vibration,the effect of the cross-flow response and in-line response in the stress of the section of pipeline span,and the impact of the average stress in the fatigue life is considered.By using the theory of spectrum analyses and fatigue analyses,a more reliable method of the fatigue life of submarine pipeline span is proposed.Finally,the effect degree of the average stress is figured out by calculating an example.