一种新型浮式单体组合结构在波浪作用下的动力响应研究

发布时间：2018-02-28 00:30

本文关键词： 单浮体结构浮式单体组合结构非线性波浪动力响应 SPH方法　出处：《大连理工大学》2016年博士论文　论文类型：学位论文

【摘要】：浮式结构物与传统的坐底式结构物相比,具有对地基承载力要求低、施工方便、有利于水质交换及海洋空间资源利用等多方面优越性,因此受到了海岸和海洋工程界的广泛关注。现阶段亟需开展波浪作用下浮式结构物的动力响应和消波性能等方面的研究,以保证恶劣海况下浮式结构物的安全和其掩护水域的平稳。本文在总结已有的浮式单体组合结构形式的基础上,提出了一种新型浮式单体组合结构形式。新型结构由一系列箱型浮体单元组成,相邻浮箱间通过顶角处的连接铰构件铰接,在浮箱底角处设置橡胶护舷来吸收浮箱间的碰撞能。针对所提出的新型浮式单体组合结构,采用光滑粒子流体动力学方法(SPH),建立了模拟非线性波浪与该种浮式单体组合结构相互作用的数学模型,并在实验室波浪水槽中进行了浮式单体组合结构的物理模型试验,以对所建立的数学模型进行验证。在建立非线性波浪与浮式结构物相互作用的数学模型的过程中,遵循了由简单到复杂的建模路线,所涉及到的浮式结构物包括三种:自由漂浮结构、系缆浮式结构和浮式单体组合结构。为了提高浮式结构流体力的计算精度,提出了一种修正的固壁边界粒子密度计算方法,有效解决了 SPH模型中固壁附近粒子密度梯度过大而导致的压力振荡问题。基于该算法建立了数值波浪水槽,模拟了非线性波浪作用下自由漂浮结构的运动响应。结合轻质弹簧模型,进一步建立了模拟非线性波浪与系缆浮式单体结构相互作用的数学模型。在此基础上,提出了浮式单体组合结构上相邻浮体单元间铰接力的新型数学模型和护舷作用力的数值计算方法,并建立起了模拟非线性波浪与浮式单体组合结构相互作用的数学模型。应用所建立并经过验证的数学模型,系统地研究了所提出的新型浮式单体组合结构的运动响应、各部分构件受力及水动力特性,并开展了浮箱间距、系缆角度和浮箱数量的参数变化比较研究,得到如下主要结论:浮式单体组合的宽度应大于入射波长;通过增加浮箱数量以增加组合结构宽度,可以在结构的背浪端形成一个相对平稳的浮式平台,以满足浮式结构的作业要求;当组合结构具有较大宽度时,能够对其背浪侧水域起到较好的掩护作用;适当减小浮箱间距和增大系缆角度都能够提升组合结构的整体稳定性。
[Abstract]:Compared with the traditional floor structure, floating structure has the advantages of low foundation bearing capacity, convenient construction, favorable water quality exchange and utilization of marine space resources, etc. Therefore, the coastal and marine engineering circles pay more and more attention to the research on the dynamic response and wave dissipating performance of floating structures under the action of waves at this stage. In order to ensure the safety of floating structures and the stability of their sheltered waters under severe sea conditions, this paper summarizes the existing floating single combination structures. In this paper, a new type of floating-unit composite structure is proposed. The structure is composed of a series of box floating body units, and the connecting hinge members between adjacent floating boxes are hinged through the top and corners of the box. A rubber fender is arranged at the bottom corner of the floating box to absorb the collision energy between the floating boxes. A mathematical model for simulating the interaction between nonlinear waves and the floating composite structure was established by using the smooth particle hydrodynamics method. The physical model tests of the floating single composite structure were carried out in the laboratory wave tank. In the process of establishing the mathematical model of nonlinear wave interaction with floating structure, the modeling route from simple to complex is followed. There are three kinds of floating structures involved: free floating structure, mooring floatation structure and floating single combination structure. In order to improve the calculation accuracy of flow force of floating structure, a modified method for calculating particle density of solid wall boundary is proposed. The pressure oscillation caused by the excessive particle density gradient near the solid wall in the SPH model is effectively solved. Based on this algorithm, the numerical wave flume is established. The dynamic response of a free-floating structure subjected to nonlinear waves is simulated. A mathematical model for simulating the interaction of nonlinear waves with a mooring cable floating single structure is established with the help of a light spring model. A new mathematical model of hinge force between adjacent floating body elements and a numerical calculation method of fender force are presented. A mathematical model is established to simulate the interaction between nonlinear wave and floating monomer composite structure. The kinematic response of the new floating monomer composite structure is systematically studied by using the established and verified mathematical model. The main conclusions are as follows: the width of floating cell combination should be larger than the incident wavelength; By increasing the number of floating boxes to increase the width of the composite structure, a relatively stable floating platform can be formed at the back wave end of the structure to meet the operational requirements of the floating structure. It can play a better sheltering role on the backwave side of the water, reduce the floating box spacing and increase the angle of mooring cable to improve the overall stability of the composite structure.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TV139.26

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