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考虑海底悬跨管道的几何非线性特征,建立了悬跨管道非线性随机振动响应分析方法。该方法结合模态分析,首先把系统隐式的非线性项转化为由模态坐标高次组合表示的显式非线性项,在此基础上引入虚拟激励法,建立结构在随机流力作用下的等效线性化系统,从而确定结构非线性随机响应。通过对某一海底管道的分析结果,表明该方法能够有效的考虑几何非线性的影响且具有很高的计算效率。同时分析了悬跨长度、管道外径和残余应力因素对计算结果的敏感性。结果表明:当悬跨长度达到较大跨度后,忽略结构几何非线性的影响,将会导致较大的误差;在较大的跨距、较浅的水深、较小的外径、初始压应力这些因素下,管道响应幅值较大。因此在这些因素存在时,要引起高度的关注。
Considering the geometrical nonlinear characteristics of the pipelines suspended above the seafloor, a nonlinear random vibration response analysis method of the suspended pipelines is established. Based on the modal analysis, this method firstly converts the implicit nonlinearity of the system into an explicit nonlinear term represented by the high-order combination of modal coordinates. Based on this method, a virtual excitation method is introduced to establish the structure under the effect of random flow Equivalent linearization system to determine the structure of nonlinear random response. The analysis result of a submarine pipeline shows that this method can effectively consider the influence of geometric nonlinearity and has a high computational efficiency. At the same time, the sensitivity of the calculation results to the span length, pipe diameter and residual stress was analyzed. The results show that when the span length reaches a large span, ignoring the influence of the geometrical nonlinearity of the structure will lead to larger errors; at larger span, shallow water depth, smaller outer diameter, initial compressive stress Under these factors, the pipe response amplitude is larger. Therefore, in the presence of these factors, to attract a high degree of attention.