基于Ochi-Mottor理论的船艏底部砰击评估方法

Research on the Slamming Method at the Bottom of Ships Based on the Ochi-Mottor Theory

针对船舶在恶劣海况下航行时的砰击问题,在船舶设计阶段应用《钢质海船入级规范》(2016)中有关船艏底部砰击强度评估的方法,采用较普遍的Ochi-Mottor理论进行砰击压力极值计算预报,选取散货船最小艏吃水装载工况,运用Sesam-HydroD三维耐波性程序直接计算砰击压力极值,根据具体的加载方式与位置,依次对船艏底部外板、纵骨、板架进行强度评估,针对砰击区域出现应力过大的板架结构,提出封堵减轻孔或增加三角肘板的建议。

Aiming at the slamming problem of ship navigating in severe sea conditions,the slamming strength at the bottom of the bow of a bulk carrier was evaluated in light of the Rules for Classification of Sea-going Steel Ships(2016)in the ship design stage.The general Ochi-Mottor theory was adopted to calculate and predict the extreme value of slam-pressure and load it according to the minimum draught of the bulk carrier.The slamming pressure extremes were directly calculated by using Sesam-HydroD.According to the specific loading mode and position,the strength of the outer shell,longitudinals and grillages at the bottom of the stern were sequentially assessed.In view of the structure of plate and frame with excessive stress in the area of slamming,suggestions of reducing the hole or adding the triangular bracket were put forward.