40m游艇船艏砰击压力有限元分析

发布时间：2018-11-26 15:42

【摘要】：船舶以一个较高的速度航行时，因为船舶和波浪之间会产生严重的碰撞，有时会造成船底暴露在水面之上。如果相对速度超过一个临界值时，船再度入水那一刻，在船艏底部、舭部、外飘等区域会产生高压峰值载荷，即砰击现象。强烈的砰击会产生严重的后果。即使在海上遭遇的不是很严重的风暴，船舶遭受砰击荷载不大，持续的颤振仍然会导致船体结构的抗疲劳强度降低。砰击会致使发生砰击的局部结构屈曲，乃至破坏。结构入水是一个短暂的过程，冲击压力作用时间非常短，但压力值一般很大，瞬时的冲击压力会导致船体变形，严重的会导致结构失效乃至解体。因此，船舶艏部砰击问题的研究对船舶安全具有非常重要的意义。以一艘40m长的钢制游艇的艏部剖面为研究对象，采用数值模拟的方法，研究船舶艏部入水砰击问题。根据砰击载荷作用的相关理论，，确定入水速度、质量和角度为主要影响因素。采用数值模拟软件，建立了船体艏部特征结构和流场二维仿真模型。通过确定船舶入水冲击的约束、欧拉域尺寸以及欧拉域内的压力载荷等，建立了数值模拟的边界条件；编制自动程序实现数据的自动输入、生成，以及对输入、输出文件进行批量管理。以砰击压力、压力峰值等作为描述砰击问题的关键参数，获得了船舶入水过程中，艏部砰击压力时程曲线。通过变换三个因素的取值，对比分析了三个因素对游艇艏部砰击压力峰值的影响规律。为验证数值模拟的准确性，建立了实船二维楔形体数值模拟有限元分析模型，模拟了与已有试验数据相同参数的入水过程。将模拟结果与已有数据对比，验证了数值模拟的约束和边界条件的准确性。
[Abstract]:When a ship is sailing at a high speed, there is a serious collision between the ship and the waves, sometimes exposing the bottom of the ship to the surface of the water. If the relative velocity exceeds a critical value, at the moment when the ship enters the water again, a high pressure peak load, I. E. slamming, will occur at the bottom of the bow, bilge and floating outside. Strong slamming can have serious consequences. Even if there is not a very serious storm at sea, the ship is subjected to a small slamming load, and the continuous flutter will still reduce the fatigue strength of the hull structure. Slamming can cause buckling and even destruction of local structures. Structure entering water is a transient process, the impact pressure time is very short, but the pressure value is usually very large, the instantaneous impact pressure will lead to hull deformation, serious will lead to structural failure and even disintegration. Therefore, the study of bow slamming is of great significance to ship safety. Taking the bow section of a 40m long steel yacht as the research object, a numerical simulation method is used to study the water slamming in the bow of a ship. According to the theory of slamming load, the velocity, mass and angle of entering water are the main factors. Using numerical simulation software, a two-dimensional simulation model of hull bow characteristic structure and flow field is established. The boundary conditions of numerical simulation are established by determining the constraints of ship entering water impact, the size of Euler domain and the pressure load in Euler domain. Write automatic program to realize automatic data input, generation, and batch management of input and output files. Using slamming pressure and peak pressure as the key parameters to describe the slamming problem, the time history curve of bow slamming pressure in the process of ship entering water is obtained. By changing the values of three factors, the effects of three factors on the peak value of slamming pressure at the bow of the swam boat are compared and analyzed. In order to verify the accuracy of the numerical simulation, the finite element analysis model of 2-D wedge body numerical simulation of a ship is established, and the process of entering water with the same parameters as the existing experimental data is simulated. The simulation results are compared with the existing data to verify the accuracy of the constraints and boundary conditions of the numerical simulation.
【学位授予单位】：集美大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U661

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