船舶横摇的安全池研究

Safe Basins of Ship Rolling

运用安全池理论计算船舶稳性。安全池在一定条件下将发生破损 ,此时船舶极易倾覆。以 Melnikov方法导出安全池破损的条件。以某型船舶为例 ,计算了该船舶安全池破损的阈值 ,对五个海况进行了安全性校核 ,并与现行规范采用的极限载荷法进行了比较。通过数值仿真绘制了各参数条件下的安全池。

In this paper, attentions are focused on the transient motions of a ship. The ship motions are described with a nonlinear differential equation combined with the effect of wind and sea waves. And its stability with the loading of wind and waves is computed using the theory of safe basin. The theory shows that the erosion of safe basin will happen under some critical circumstances. And these circumstances are dangerous for a ship because any small disturbance to the ship motion will lead to the capsizing. The critical conditions of erosion are given using Melnikov method. Analysis shows that the stability of a ship is affected by damping, wave frequency, and loading of wind and sea waves. Safe basin erosion is caused by low frequency waves and heavy load of wind and sea waves. And it is difficult to lead to safe basin erosion with heavy damping. The stability under five marine conditions of a vessel is computed. And the results are compared with the traditional regularities. The result of this vessel shows that the vessel's stability is strictly restricted by the traditional regularities. The safe basins under different circumstances are also presented.