船舶在规则横浪中的奇异倾覆

采用非线性动力学理论研究了船舶在风浪中的抗倾覆能力．用近似方法求解描述船舶横摇运动的非线性微分方程，获得船舶运动的稳态解．运用分岔分析方法结合Floquet理论对该稳态解进行稳定性分析，结果显示，在一定的波浪条件下，船舶运动将经历倍周期分岔而进入混沌，从而导致船舶的倾覆．由此证明，运动稳定性丧失也是船舶倾覆的一种模式，因此将倍周期分岔归纳为船舶倾覆的机理之一．选择船舶的固定横倾角作为一个敏感因素来探讨它对于船舶抗倾覆能力的影响．结果表明，船舶的固定横倾角会极大地损害船舶在风浪中的稳性．

Undesirable Ship Capsizal in Regular Beam Sea

Since the classical linear dynamics of ship motion can not explain some undesirable ship capsizal, the nonlinear dynamic theory was adopted to study the anti capsize capacity of ship. By using the approximate method, the solution to the nonlinear differential equation which governs the ship motion in regular beam sea is attained. The stability of this solution is analyzed based on the bifurcation method and Floquet theory. The result shows that the ship motion will become chaos after the double period bifurcation and lead to capsizal. The stability loss of ship motion is also one of the approaches resulting in the ship's capsizal. Therefore, double period bifurcation is defined as a capasizal mechanism. The biased angle is originally selected as a sensitive factor to study its effects on the ship's anti capsizal capacity. The research shows that biased angle will seriously damage the ship's stability, so that it is very important to control the biased angle for ship's safety.