Being aimed at the characteristic of the large slenderness ratio of riser in deepwater, the cable model is employed to calculate the nonlinear stiffness matrix. The correctness of this model is validated by the experimental results. The fluid-structure interaction of the discrete nodes was considered in the model. For evaluating the random vibration, the vortex induced lift of two-dimensional riser is calculated using discrete vortex method to obtain the load spectrum for the calculation of Pseudo-excitation. The vortex induced vibration is considered as a stationarity random process. The response of riser to vortex induced excitation is calculated using pseudo-excitation method. The fatigue damage rate of the riser per year is evaluated and the service life of the riser can be predicted based on the P-M criterion.%针对深海立管长细比非常大的结构特性,使用索模型单元计算结构的非线性刚度阵,并验证了模型的有效性；在立管离散点处的平面上考虑结构与流体的耦合作用,采用离散涡方法计算了立管二维模型在均匀海流下的涡激升力载荷,为随机振动分析提供载荷谱,用于构造虚拟激励.最终将立管的涡激振动看作平稳随机过程,采用随机振动理论中的虚拟激励法求解立管在涡激力激励下的响应.基于P-M准则,对响应进行计算得到立管的年损伤率,实现了深海立管的疲劳损伤预报.
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