隔水管在工作过程中会受到浮体施加的升沉作用力,该作用力会使得轴向力发生周期性变化,引起参激振动,因此研究隔水管参激振动对避免隔水管发生参激共振具有指导意义。考虑钻井液对隔水管的作用力,通过微元法建立了隔水管横向振动控制方程。假定轴向力周期性变化,利用主坐标分析法得到隔水管Mathieu方程,基于Floquet理论对隔水管进行参激振动稳定性分析,得到了系统参激稳定图。结果显示,主不稳定区发生在隔水管固有频率二分之一附近。进一步研究阻尼对系统参激不稳定区的影响,发现阻尼使得隔水管参激稳定区域增加,并且随着阻尼增大,稳定区域增大。该研究对隔水管设计过程中避免参激共振具有一定参考意义。

The riser will be subject to platform heave forces during operation, which causes the axial force to change periodically, causing parametric vibration.Therefore, it is instructive to study the parametric vibration of the riser to avoid parametric resonance.This paper considers the force of the drilling fluid on the riser and establishes the transverse vibration control equation of riser by using the micro-element method.Assuming that the axial force changes periodically, the Mathieu equation of the riser is obtained. And the parametrically excitedvibration stability analysis of the riser is performed based on the Floquet theory.The results showed that the main instability zone occurred near one-half of the natural frequency of the riser.With further study for the influence of damping on the system parameter stability, it is found that the damping increases the stability area of the riser, and the larger the damping, the greater the stable area is.The research of this paper provides reference for avoiding theparametricallyexcited resonance in the design of the riser.