According to the motion characteristics of the submerged floating tunnel,the cable is assumed to be a non-linear beam model hinged at both ends,and the motion of the tube body is simplified to a mass point motion with two degrees of freedom.Conside-ring that the cable is under the sea current environment for a long period of time,its forward vortex excitation force is in the same direc-tion as the sway motion of the tube,and the motion response of the cable may change significantly.Therefore,it is necessary to estab-lish the non-linear equation of the cable with forward vortex induced vibrations and solve this equation by Galerkin method and Runge-Kutta method.The structure of a typical suspension tunnel was selected for numerical analysis.The results show as follows.In the first three orders of the cable mode,the second and third order mode amplitude is much smaller than the first order mode amplitude,which can be neglected.The effect of parametric excitation on the cable can enable the cable to get into the stability more quickly and the in-crease in displacement amplitude has a significant effect.The influence of the parametric excitation on the vortex induced vibration in the forward direction is related to the amplitude and frequency of the excitation at the top of the cable.
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