基于动边界技术的单向张拉膜结构流固耦合效应研究

发布时间：2018-03-09 13:39

本文选题：单向张拉膜结构　切入点：动网格技术　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：膜结构是二十世纪中期发展起来的一种新型大跨度空间结构体系,近年来应用十分广泛。该类结构具有质量轻、刚度小、阻尼小等特点,风荷载往往成为结构设计中的主要控制荷载。膜结构在风荷载作用下容易产生较大的变形和振动,这种变形和振动反过来也会影响结构周围的流场,进而影响到膜面风压分布,产生流固耦合效应,在膜结构的抗风设计中需要特别关注。由于膜结构流固耦合问题异常复杂,国内外对这一问题的研究并不成熟,研究方法主要有三种:解析方法、CFD数值模拟方法和气弹模型风洞试验方法,目前看来,数值模拟与气弹模型试验相结合的方法对膜结构流固耦合问题的研究具有重要意义。本文基于FLUENT平台的动边界技术,将单向张拉膜结构的流固耦合问题简化为运动边界对流场影响的问题进行了研究。首先针对单向膜结构的耦合流场,进行了动边界控制方法与动网格更新方法的选择,确定了流场的网格形式等问题。然后基于10m/s风速工况下的单向膜结构气弹模型试验,运用动边界技术进行了流场再现;并利用数值风压进行了膜结构的位移响应分析,流场与结构位移的计算结果均与试验结果吻合较好,说明了该方法用于研究单向膜结构流固耦合效应的可行性。在此基础上,对单向膜结构指定简谐运动形式,对比了膜面平衡位置、振动幅度、振动频率及振动模态等参数对流场的影响,探讨了简谐振动下的流固耦合效应。结果表明,平衡位置越大漩涡越明显,对流场形式起主要作用,进而影响了膜面风压分布;结构振幅越大、振动频率与模态越高,振动对流场的耗散作用越明显,流场将趋于稳定,并且振动频率控制了流场主频,加快了流场的发展。然后,根据不同风速下气弹模型试验获得的位移时程,对膜结构实际振动情况下的流场进行了模拟分析,探讨了随机振动下的单向膜结构流固耦合效应。结果表明,当超过一定风速后,结构振动明显增强,将在一定程度上减弱膜面平均风压值,并改变了脉动风压分布形式。
[Abstract]:Membrane structure is a new type of large span space structure system developed in the middle of 20th century. It is widely used in recent years. Wind load often becomes the main control load in structural design. Membrane structure is prone to produce large deformation and vibration under the action of wind load, which in turn will affect the flow field around the structure, and then affect the wind pressure distribution on the membrane surface. Due to the fluid-structure coupling effect, special attention should be paid to the wind-resistant design of membrane structure. Due to the complexity of the fluid-structure coupling problem, the research on this problem is not mature at home and abroad. There are three main research methods: analytical method, CFD numerical simulation method and Aeroelastic model wind tunnel test method. The combination of numerical simulation and Aeroelastic model test is of great significance to the study of fluid-solid coupling of membrane structures. This paper is based on the dynamic boundary technique of FLUENT platform. The fluid-solid coupling problem of unidirectional tensioned membrane structure is simplified to the influence of moving boundary flow field. Firstly, the dynamic boundary control method and the dynamic grid updating method are selected for the coupled flow field of unidirectional membrane structure. The mesh form of the flow field is determined. Based on the Aeroelastic model test of the unidirectional membrane structure under the wind speed of 10 m / s, the flow field is reproduced by using the moving boundary technique, and the displacement response of the membrane structure is analyzed by the numerical wind pressure. The calculated results of flow field and structural displacement are in good agreement with the experimental results. The feasibility of using this method to study the fluid-solid coupling effect of unidirectional membrane structures is illustrated. On this basis, a simple harmonic motion form is designated for unidirectional membrane structures. The fluid-solid coupling effect under simple harmonic vibration is discussed by comparing the effects of the flow field such as the equilibrium position, vibration amplitude, vibration frequency and vibration mode. The results show that the larger the equilibrium position, the more obvious the vortex is. The distribution of wind pressure on the membrane surface is mainly affected by the form of the flow field, the larger the amplitude of the structure is, the higher the vibration frequency and mode are, the more obvious the dissipative effect of the vibration flow field is, the more stable the flow field will be, and the vibration frequency controls the main frequency of the flow field. The development of the flow field is accelerated. Then, according to the displacement time history obtained from the Aeroelastic model test under different wind speeds, the flow field under the actual vibration of the membrane structure is simulated and analyzed. The fluid-solid coupling effect of unidirectional membrane structure under random vibration is discussed. The results show that the vibration of the structure increases obviously when the wind speed exceeds a certain wind speed, which will weaken the average wind pressure on the membrane surface to a certain extent and change the distribution of fluctuating wind pressure.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU383

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