【作者】 邹忠胜；

【导师】 杜嘉立；

【作者基本信息】 大连海事大学 ， 交通运输工程， 2010， 硕士

【摘要】 锚泊船走锚和船舶积冰是海上船舶二个比较常见的海冰灾害。冰情较严重时,中小型船舶在海冰的作用下容易走锚,造成碰撞、搁浅等严重事故。目前,对船舶冰区安全锚泊的研究大多停留在经验方法。由于缺乏量化的计算,经验方法在实践应用中存在较大的局限性。另外,在适宜的气象条件下,海浪飞沫积冰对中小型船舶产生不容忽视的危害,甚至导致船舶倾覆。但是在实践操作中,船舶积冰的危害没有引起足够的重视。因此,对冰区锚泊船舶的受力和海浪飞沫积冰对船舶的危害进行定量计算和分析,深化广大船员对船舶受力和积冰危害的认识,对提高船舶冰区安全航行有一定的指导意义。论文分析海冰与船舶作用时的破坏方式,引用海冰对结构物的静冰力公式,综合风、流的影响,计算船舶在冰区锚泊时所受的外力。在此基础上,假设锚在任何情况下均能发挥最大抓力,计算船舶在外力作用下的最小出链长度。由计算可知：船舶的最小出链长度随着风速、顶偏角、冰厚的增大而增大；在一般气象条件下,冰厚4cm的海冰导致三千吨级船舶走锚；冰厚9cm的海冰可导致万吨级船舶走锚。因此,吨位较小的船舶应尽量避免在冰区锚泊。论文对船舶的海浪飞沫上浪模式进行了分析,建立适用于计算海浪飞沫上浪的随船坐标系。在此基础上,引用中小型船舶海浪飞沫上浪的经验公式,计及海浪飞沫的运动和冷却,对船舶的积冰量、积冰分布进行了计算。根据上述结果,计算积冰对船舶的浮性、稳性的影响。假设船舶积冰持续24小时,由计算可知：顶偏角0°-45°,船舶稳性衡准数K随顶偏角增大而减小；顶偏角45°-90°,K随之增大而增大；顶偏角45°左右,K达到最小值,在较大船速、风速条件下,K＜1,船舶有倾覆危险。另外,K随着风速、船速的增大而减小。因此,综合考虑各种因素,船舶应以较小顶偏角、船速航行。如果预计风力较大,船舶应避风。通过论文的分析与定量计算,深化船员对冰区锚泊船舶的受力和积冰危害的认识,为冰区安全航行提供决策依据。更多还原

【Abstract】 Ship dragging and ship icing are two of the common disasters of sea ice when the ships are at sea. Under severe ice conditions, small and medium sized vessels are easy to drag, being caused collisions, groundings and other serious accidents. Currently, the study of ship anchoring in ice zone mostly remains on empirical methods. Lack of quantitative calculation, there are limitations of empirical method in practical application. In addition, in suitable weather conditions, icing of sea spray causes hazards to the ship that can not be ignored, or even leads the ship to capsize. However, the hazards do not cause enough attention in practice. Therefore, quantitative calculation and analysis of force of anchoring ship and hazards of icing, enable the crew to quantitatively knowledge force of anchoring ship, and recognize hazards of ship icing, take appropriate measures.This paper analyzes failure of sea ice when ice acts on the ship, cites static ice force formula between sea ice and structures, takes wind and current into account, then computes the external force of anchoring ship. On this basis, assuming that anchor can play the maximum grip strength in all conditions, the minimum chain length under external loads of ship can be calculated.Known from the calculation, under normal weather conditions, sea ice of thickness around 4cm leads 3000-ton ship to drag. Sea ice of thickness around 9cm leads ship in the 10 thousand ton class to drag. Therefore, the light-tonnage vessel should avoid anchoring in the ice zone.In this paper the model of sea spray is analyzed, and the following-ship coordinate system being suitable to calculate sea spray is set up. On this basis, empirical formula of sea spray on small and medium sized ship is quote. Taking into account the movement and cooling of droplets, the ice distribution is calculated. According to the ice distribution, the ship’s buoyancy and stability can be calculated. Assuming that ship icing for 24 hours, known from the calculation, as the top angle from 0°to 45°, the number of ship stability criteria decreases with the top angle; as top angle from 45°to 90°, it increases; as top angle from 45°, it comes to minimum, and in the larger vessel’s as the wind speed, boat speed increased, it decreases. Therefore, considering various factors, the ship should navigate with smaller top angle and the smaller speed. If the wind is expected to increase, vessels choose to shelter from the wind.Through analysis and quantitative calculation, crew can deeply know the force of anchoring ship and hazards of icing.lt can provide safe navigation decision-making when the ships are at sea.更多还原