考虑阻尼海底悬跨段管道的动力特性及允许悬空长度

以海底悬跨段输液管道为研究对象，考虑管道结构阻尼、流体附加阻尼、管内流体流动及管道轴向力和压强的作用，对其进行受力分析，导出管道振动微分方程，进而得到管道动力特性方程。用Hermit插值函数对管道的动力特性方程进行离散得到有限元表达式，采用复模态分析法，求得管道的自振频率。为防止管道发生横向涡激振动，用约化速度作为控制条件，确定管道允许悬空长度。结果表明，管道允许悬空长度随着内流流速、轴向压力和管内压强的增加而减小，随着轴向拉力的增加而加大。

Allowable span length of submarine pipeline considering damping

This paper focuses on the free span of submarine pipelines. The lateral motion and dynamic characteristic equation of submarine pipelines subjected to damping, external steady current, internal flow, axial force and pressure was established. By using Hermit interpolation function, the dynamic characteristic equation is discretized, and the complex modal analysis method is used to find the natural frequencies of the free span of submarine pipelines. In order to avoid VIV, the reduced velocity is used as a control parameter, and the allowable span length of submarine pipelines is thus derived. The result indicates that the allowable span length of submarine pipelines decreases with an increment in the velocity of internal flow, compression and pressure, and increases with an increment in tension.