基于SESAM的远洋秋刀鱼渔船结构强度评估

Structural strength evaluation of the saury fishing vessel based on SESAM

远洋渔船结构设计主要参考《钢质远洋渔船建造规范》,船长小于65m不需要总纵强度计算;若大于65m,其波浪弯矩参考商船的经验公式确定,而渔船与商船在船型上差异较大,且渔船真实作业工况环境载荷也很难简单地用经验公式计算。本研究考虑渔船实际作业工况和所处海域海情,计算获取更为真实的外载荷,以便更精确地计算渔船结构应力与变形,达到强度评估、改进渔船结构设计的目的。通过SESAM软件建立秋刀鱼渔船三维模型,对渔船丰收返港、空载到港和横倾捕鱼3个典型作业工况进行整船有限元分析。结果显示:驾驶室后舱壁与艉楼甲板、救生甲板相交处,艉楼甲板和主甲板相交舱壁处的应力较大。为此,设计秋刀鱼渔船时建议重点关注这些应力集中区域,做好结构过渡。此外,由于机器布置靠近首尾,鱼舱布置在船体中部,考虑各种典型工况,建议将压载舱室设置在中部,以平衡其重量重心、减小附加弯矩。

The structural design of the ocean fishing vessel is mainly based on the Code for Construction of Steel Ocean Fishing Vessels.No calculation of the total longitudinal strength is required for a vessel with length less than 65 m.If it is greater than 65 m,its wave bending moment is determined by the empirical formula of the merchant ship,but the difference between the fishing vessel and the merchant ship is large,and the environmental load of the fishing vessel in real working conditions is difficult to express easily by the empirical formula.In this paper,considering the actual working conditions of the fishing vessel and the sea conditions,the calculation for the more realistic external load is carried out in order to more accurately calculate the structural stress and deformation of the fishing vessel,achieve the strength assessment and improve the structural design of the fishing vessel.The three-dimensional model of the saury fishing vessel was established by SESAM software,and the finite element analysis of the whole vessel was carried out for three typical working conditions of fishing vessel returning to port,no-load arrival and heeling.The results show that the rear bulkhead of the cab intersects the stern deck and the rescue deck,and the stress at the intersecting bulkhead between the stern deck and the main deck is greater.To this end,it is recommended to focus on these areas of stress concentration when designing a saury fishing vessel,and make a structural transition.In addition,since the machine arrangement is close to the head and tail,the fish tank is placed in the middle of the hull.Considering various typical working conditions,it is recommended to set the ballast tank in the middle to balance its weight center of gravity and reduce the additional bending moment.