大倾角搁浅船舶扳正过程分析

Uprighting process analysis of big-angle tilted aground ship

在研究大倾角搁浅船舶的扳正过程中,计算了难船扳正力、横倾角和吃水。根据搁浅船舶的受力特点,建立了其力学模型,分析了扳正过程中横倾角、吃水、入泥深度与海底泥土性质对船体的影响。利用GHS软件模拟搁浅船舶的扳正过程,以某搁浅液化气船舶为例,求解了其扳正过程中船体扳正力、总搁坐力、剪力、弯矩和转矩,比较了难船不同扳正方案,分析了难船的扳正方式、搁坐位置、上层建筑与储气罐对难船打捞的影响。分析结果表明:在扳正过程中,3个方案的力学参数的变化趋势是一致的。最大扳正力相差较大,差值为9.1%~20.0%。搁坐力、剪力和弯矩均在横倾角为-55°^-50°时达到最大值,船体虽然在该阶段不需加载较大的扳正力,但仍应该注意船体的受力情况。在横倾角为-120°^-100°时,转矩变化非常剧烈。弯矩和转矩均出现了反向变化的现象,威胁船体结构的安全,扳正中应该谨慎处理。选择合适的扳正方案时应该综合考虑扳正力施力点的位置和扳正过程对船体与环境安全的潜在威胁。

In order to study the uprighting process of big-angle tilted aground ship,the uprighting force,heel angle and draft of the ship were computed.The mechanical model of aground ship was established based on its mechanical characteristics,and the influences of heel angle,draft, driving depth and natural properties of seabed soil on hull were analyzed.Taking a big-angle tilted aground LNG tanker as an example,the uprighting force,total aground force,shear, moment and torque of the tanker in the uprighting process were solved by the simulation of GHS software.Different uprighting schemes were compared,and the influences of uprighting modes, aground positions,superstructures and liquid gas storage tanks on uprighting process were analyzed.Analysis result shows that the changing trends of mechanical parameters of three schemes are similar.The larger differences are 9.1%-20.0% among the maximum uprighting forces of three schemes.The aground force,shear force and moment reach the maximums when the heel angle ranges from -55° to -50°.The stage need not exert larger uprighting forces,but＆amp;nbsp;the force situation of hull should be noticed.The torque changes enormously when the heel angle ranges from -120°to -100°.The opposite changing phenomenon of moment and torque directly threatens the safety of hull structure,so it should be handled with more care during uprighting process.The appropriate uprighting scheme is selected by considering the positions of points of uprighting forces and the reliability for the safety of hull and environment during uprighting process.1 tab,9 figs,21 refs.