| Submarine cable transmission project is an important part of the construction of cross-sealine networking projects.It plays an important role in realizing the internationalization of power grids and the interconnection of regional power grids.It has been widely used in power grid interconnection,sea island power supply,offshore oil platform power supply,etc..After the sea cable is laid on the seabed,the suspended water is generated due to the erosion of the seabed by the water flow.When the water flows through the suspended section,vortex-induced vibration is induced,which leads to fatigue cracking of the lead sheath and an accident.Vortex-induced vibration of submarine cable is a very complex fluid-solid coupling problem.The natural vibration frequency and the cable vibration mode are important components of the vortex-induced vibration problem.In this paper,it studies the natural vibration frequency and vibration mode of submarine cable by theoretical analysis and model test.Firstly,the theoretical analysis of the natural frequency of the submarine cable is carried out.According to the basic data of the existing engineering,it selects three representative span lengths.The calculation is based on the theory of different boundary conditions(hinge support,smooth support,fixed support).Analyzing that the natural frequencies and vibration modes of submarine cables change with different span lengths and different boundary conditions.Secondly,three suspension span lengths were also selected in the physical model test,and the natural vibration frequency and vibration mode of the submarine cables with different tensile forces and different overhang heights were measured and analyzed.Finally,through the comparative analysis of the theoretical value and the measured value,the relationship between the natural frequency of the submarine cable and the modal and tensile force,the overhang height,the boundary condition,the elastic modulus and other variables are determined. |
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