高海况下超大型船舶非线性水弹性时域方法及外张砰击的研究

With increasing demands for huge dimensions of ships, the prediction of wave load responses of ultra-large vessels has drawn more and more people’s attentions. Especially in high sea state, the obvious nonlinear characteristic of load responses becomes main difficulty of research on ultra-large vessels. This research aims at establishing the method of load responses prediction and flare slamming of ultra-large vessels in high sea state. Firstly, a kind of 3-D nonlinear hydroelasticity time domain method will be presented with the nonlinear factors considering the incident wave force, diffraction wave force, restoring force caused by the instantaneous position variation of body surface and the slamming force. A semi-analytical method that fluid damping in high frequency is truncated will be proposed to obtain time domain delay function; Secondly, in order to study ultra-large vessels load characteristic and verify the reasonability of the present method, the wave load experiments of segmented ship model will be carried out in the test tank for a container ship with four different bow line types; Finally, based on test data, the flare slamming mechanism will be studied, considering the effect of sea state, motion responses and other factors, the calculation formulas of flare slamming time and coefficient will be presented respectively. The “degree of flare” will be introduced to study the effort of variable bow line type on slamming loads，the variation laws of slamming loads with degree of bow flare will be analyzed to provide reference for ship designers. This research will be not only suitable for container ship, but also other ship types.

随着船舶尺度不断增大，超大型船载荷响应的预报越发引起人们的关注。特别是高海况下，载荷响应中明显的非线性特征成为制约超大型船研究的主要瓶颈。本课题旨在建立一套针对高海况下超大型船舶载荷响应预报和外张砰击的研究方法。首先，提出一种能够同时计及瞬时物面引起的入射波力、绕射波力、静水回复力非线性以及砰击力的三维非线性水弹性时域方法，并提出一种半解析法对高频流体阻尼进行截断处理进而得到时域延时函数；其次，为探寻超大型船力学特性并验证理论方法，在拖曳水池对四条艏部线型不同的集装箱姊妹船进行分段模型自航试验；最后，基于试验数据，探寻外张砰击机理，考虑海况及运动响应等因素影响，提出外张砰击时间和砰击系数的计算公式，并引入“外张度”这一概念，分析艏部线型变化对砰击载荷的影响，揭示砰击载荷随外张度的变化规律，为船舶设计人员提供参考。本课题的成果将不仅适用于集装箱船，还能为其他船型的研究提供理论和试验依据。

基金主持人着眼于国内船海领域热点问题，针对超大型船，特别是高海况下载荷响应的理论预报和试验方法展开了研究。本课题成功地建立了一套针对高海况下超大型船舶载荷响应预报和外张砰击的研究方法。首先，提出了一种能够同时计及瞬时物面引起的入射波力、绕射波力、静水回复力非线性以及砰击力的三维非线性水弹性时域方法，并提出了一种半解析法对高频流体阻尼进行截断处理进而得到时域延时函数；其次，为探寻超大型船力学特性并验证理论方法，在拖曳水池对四条艏部线型不同的集装箱姊妹船进行了一系列分段模型自航试验，通过分析测量结果，得到一些较有价值的规律和结论；最后，基于试验数据，分析了外张砰击机理，考虑海况及运动响应等因素影响，提出了一套外张砰击时间和砰击系数的计算公式，并引入“外张度”这一概念，分析了艏部线型变化对砰击载荷的影响，揭示了砰击载荷随外张度的变化规律，为船舶设计人员提供参考。本课题的成果将不仅适用于集装箱船，还能为其他船型的研究提供理论和试验依据。主持人如期完成各项任务，基金资助期间发表SCI论文5篇，已检索3篇。发表EI论文4篇，全部检索。发表已授权国家发明专利一项。