为了提高船舶航行安全性,基于非线性动力学理论,以系统运动的全局分岔为出发点,研究了船舶在随机横浪中全局稳定性.将船舶在随机横浪中所受的随机激励项处理为一窄带随机噪声,考虑阻尼力矩和恢复力矩非线性因素的影响,建立了船舶在窄带随机噪声作用下的单自由度非线性随机微分方程,采用随机Melnikov方法对船舶在随机横浪中的全局稳定性进行了分析,并用安全池法进行了验证.研究表明,有界噪声模型可以很好地模拟船舶所受的随机外激励,当噪声强度大于临界混沌值时,船舶出现随机混沌运动,这种不稳定极易导致船舶倾覆.%In order to improve the safety of ship navigation on the sea, the global stability of a ship in stochastic beam seas was researched using the global bifurcation method, based on the nonlinear dynamics theory. While considering the stochastic excitation term as bounded noise as well as the influence of nonlinear damping and a nonlinear righting moment, a stochastic nonlinear single degree of freedom differential equation for ship rolling was established. The random Melnikov mean-square criterion was used to analyze the global stability of this system and the results were verified by the safe basin method. The research indicates that the bounded noise can simulate the wave excitation quite well, and if the noise exceeds the threshold value, the ship will undergo stochastic chaotic motion. That will lead to instability of the ship and possibly even to capsizing.
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