随机海浪中船舶安全概率的数值模拟

Numerical Simulation of Ship's Safe Probability in Stochastic Waves

近年来国外发展起来的安全盆思想为衡准船舶动稳性特性开辟了一条新的途径,本文将安全盆的思想进行了延续和拓展。首先简要的介绍了求解微分方程的数值方法———谐加速度方法的基本思想与计算步骤,然后以一条渔船为例,引进ISSC双参数海浪谱,在构建船舶横摇运动微分方程时考虑了船速和遭遇浪向角的影响,应用谐加速度方法对船舶在随机海浪下的非线性横摇运动方程进行了数值求解,结合数理统计的知识,得到了随机海浪中4参数的船舶安全概率,分析了波高、波浪特征周期、遭遇浪向角、船速以及海浪随机相位角等因素对船舶安全概率的影响。

The safe basin theory developed abroad recently provides a new approach to predict the probability of ship＇s dynamic stability. The theory is extended and developed in this paper. The basic idea about harmonic acceleration method, which can be used to solve differential equations, is introduced briefly with the calculation steps. A fisher with 30.7m long and 6.9m wide is taken as an example. The ISSC wave spectrum is used for the description of the excitation. The velocity and heading angle of ship are considered in the nonlinear rollmotion differential equation. The nonlinear dynamic response of ship is simulated by the harmonic acceleration method. The safe probability p. （H, T,X,U） is obtained from a four parameterized function combining the statistic knowledge. Several factors including the wave height, the wave period, the heading angle, the velocity of ship and random phase angle of waves are taken into account in analyzing their influences on ship＇s safe probability.