经典式Spar平台垂荡-纵摇耦合混沌运动研究

该文基于Lyapunov指数研究经典式Spar平台主体垂荡-纵摇非线性耦合的混沌运动。建立了规则波浪中平台主体垂荡-纵摇耦合非线性微分方程，以经典式Spar平台为例，数值计算了响应的最大Lyapunov指数谱及分岔图，在波高和波浪频率构成的平面上，计算了平台不稳定纵摇运动的参数域。结果表明，平台运动形式对波浪激励频率非常敏感，随着波浪频率的改变，Spar平台发生1/2亚谐运动、概周期运动，当波浪频率接近垂荡固有频率时，发生混沌运动。

STUDY ON THE CHAOTIC MOTION OF COUPLED HEAVE AND PITCH OF CLASSIC SPAR PLATFORM

The chaotic motion of nonlinear coupled heave-pitch of the classic Spar platform hull is studied by the Lyapunov exponent in this paper. The nonlinear differential equation of the coupled heave-pitch of the platform hull is established in the regular wave. Taking the classic Spar as an example, the maximum Lyapunov exponent spectrum and the bifurcation diagrams are calculated and the parameter domain for unstable pitch motion is calculated. The results show that the platform motion is sensitive to wave frequency. With changing of wave frequency the platform exhibits 1/2 sub-harmonic motion and quasi-periodic motion. When the wave frequency approaches the natural frequency of heave, the platform exhibits chaotic motion.