【作者】 陈锋；

【导师】 王春江； 李向民；

【作者基本信息】 上海交通大学 ， 结构工程， 2010， 硕士

【摘要】 索结构广泛应用于悬索屋盖、幕墙结构、输电塔线体系、桥梁结构、桅杆结构等建(构)筑物中,具有质量轻、抗弯刚度小等特性。索结构的风振影响不可忽视,因风振失稳导致的事故时有发生。风荷载具有随机性与空间相关性,而索结构自身振动特性亦非常复杂,迄今索结构的风振响应研究仍是风工程领域的研究热点,仍有较多机理性的研究有待推进。目前索结构风振方面的研究已开始考虑流体与结构之间的相互作用即流固耦合效应,但已有的一些流固耦合实验及数值模拟多采用节段模型或二维近似模型,边界条件等因素的选择使计算结果具有一定的偏差。本文对长索的全结构三维模型流固耦合效应进行了多参数模拟分析。针对流固耦合分析方法、索结构振动机理、风振响应分析等方面进行了比较系统的研究。介绍了索结构风工程领域的研究现状,指出存在的主要问题,并提出本文的研究目标和工作重点。在索振分析方面,本文介绍了结构风环境的大致情况,阐述了常用的结构振动分析方法,并对最常见的索振类型及其发生机理进行了探讨。在数值风洞方面,本文介绍了结构风工程领域风洞模型试验、风速时程数值模拟技术等方面的进展情况。利用CFD(计算流体力学)数值风洞技术对封闭式双坡屋面及封闭式拱形屋面两类建筑屋面风压分布特性进行了模拟,与规范进行对照验证了数值风洞技术的可行性。在流固耦合方面,本文介绍了计算流体动力学及计算结构动力学的基本原理,分析流固两相介质交界面处的耦合机理,接着讨论了流固耦合分析方法的研究进展,并简要介绍了本文采用的ANSYS-CFX环境的计算流程和基本原理。在长索风振响应分析方面,本文针对稳态风场中的流固耦合响应进行了多参数计算分析,与不考虑流固耦合效应的结果进行了对比得出一些有关的结论。首先对圆截面单索进行分析,针对不同的索倾角、风向角、风速及预应力水平等多种工况,分别建立了计算模型,采用层流模型与k-ω湍流模型对比计算,分析研究了节点位移时程曲线及索表面点风压时程曲线等风振响应特性。对D字形截面的水平索,计算了三种不同风速条件下的风振响应曲线。然后对两并列长索及两串列长索进行了流固耦合风振响应分析,并研究了不同间距下的响应特性。最后本文作者对全文的研究工作进行了总结,并指出部分有待于深入研究的问题。更多还原

【Abstract】 Cable structures are widely used in constructions including cable suspended roof, curtain wall, transmission tower-line system, bridge and guyed mast. Wind effects become one of the dominating factors that must be considered due to the low weight and bending stiffness for structures. Since damage and failure of cable occur often in wind, wind-induced vibration of cable structures is paid more and more attention by both engineers and researchers. Wind load applied on cable structures is random and space-correlated, and cable itself has complicated mechanical properties. Wind induced response of cable structures is the research focus in wind engineering field, and the research on mechanism is still need to be promoted. At present some researchers already start studying cable’s vibration on fluid-structure interaction(FSI) effect, but section model or two-dimensional approximate model is usually adopt in the study of cable’s FSI effect by wind tunnel tests or numerical simulation, which has low calculation accuracy..Three-dimensional model of long cable structures is used in this paper for FSI multi parameter analysis. In this paper the author focuses on the following aspects: analysis methods of FSI, wind field simulation, vibration mechanism of cable structures and dynamic response of wind-induced vibration. Firstly, the research on wind engineering of cable structures is reviewed, the existing major questions are presented, and the future research work and target is discussed.Secondly, the basic theory of structural wind engineering are introduced, analysis methods of cable’s vibration are investigated, different types of cable’s wind-induced vibration and their mechanisms are analyzed.Thirdly, techniques of wind tunnel tests and numerical simulation of wind speed time series are studied. Wind pressure coefficient of a closed-end double slope roof and an arched roof are calculated by computational fluid dynamics numerical simulation technique, compared with national load code. Forthly, basic principles of computational fluid dynamics(CFD) and computational structure dynamics(CSD) are described; coupling mechanism and research progress of FSI are discussed; calculation scheme and basic principle of FSI under ANSYS-CFX environment are introduced.Then, long cable’s dynamic response on FSI effect in steady wind field are calculated and analyzed under multi-parameter condition and some useful conclusions are obtained, compared with results on rigid models. Single steel cable with circular section and D shape section are simulated first, then several models with different parameters,such as inclined angle, yaw angle, wind velocity and prestress level of cable. K and omega turbulent model and laminar model are used to simulate fluid flow seperately. Then two series connected cables and parallel connected cables are simulated. Time history curves of displacement, pressure, stress and some wind-induced vibration rules are obtained.Finally, based on the research work in this dessertation, some useful conclusions are drawn and some problem to be furtherly considered are indicated.更多还原