考虑预应力分布的立管涡激振动特性分析

针对立管结构中存在着复杂预应力分布的现象,提出了考虑复杂预应力的立管涡激振动问题.基于梁结构理论,从应力-应变方程出发,建立了含复杂预应力的立管结构运动控制微分方程.对剪切流作用下典型顶张立管的涡激振动问题进行了数值计算,对比了复杂预应力对立管结构的自然频率、振型及典型节点振动特性的影响.计算结果表明,复杂预应力的存在对立管结构的动力特性有着重要的影响,特别是结构自然频率.文中所提出的方法可为复杂载荷作用下的立管结构动力特性问题的研究提供新思路.

Analysis of Vortex Induced Vibration of Marine Riser Under#br# the Consideration of Pre stress Force Distribution

In present research, the problem of vortex induced vibration (VIV) of marine riser structure with complex pre stress force distribution is considered. Based on the Euler Bernoulli beam theory, according to the stress strain formula, differential equations of the influence with complex pre stress force distribution on riser structure are established. At the end, a top tensioned riser (TTR) which is under shear flow loading is taken as an example, the influence of natural frequency, mode shape, and VIV response characteristic by complex pre stress force distribution are investigated. The result shows that the distribution of complex pre stress force has a significant influence on the riser structural dynamic characteristics, especially on the natural frequency. It is shown that the method proposed in this research provides a new approach to analyze the VIV problem of riser structure with complex loading.