速度梯度对立管涡激振动疲劳损伤影响分析

摘要

将钢悬链式立管SCR(Steel Catenary Riser)简化为索模型,首先对立管进行了模态分析,并通过模态叠加法计算了涡激振动响应.然后基于瑞利分布,对立管进行了疲劳损伤分析,得到了立管的年疲劳损伤率.以1500 m水深Spar平台相连接的钢悬链式立管为例,通过改变剪切流的来流梯度来研究其对疲劳损伤产生的影响.计算结果表明·立管最大疲劳损伤通常出现在边界区域,并且随着来流速度梯度的减小,立管的能量激励区域增大,疲劳损伤也随之变大.%The SCR (Steel Catenary Riser) is simplified into a cable model in this paper. First the modal analysis is performed, then the response of vortex induced vibration(VIV) is calculated by modal superposition method. Based on Rayleigh distribution,the fatigue damage analysis induced by VIV is carried out to calculate the yearly fatigue damage rate of the riser. A 1 500 m Spar platform-riser system is studied, the paper is conducted through changing the gradient of the sheared flow to study its influence on the fatigue damage. The result show that the max fatigue damage occurs on the riser's boundary area, and with the reduction of the flow gradient the increase of the excited area of the riser, the fatigue damage is subsequently greatens.