桥梁拉索振动控制的椭圆形薄壁结构调谐质量阻尼器研究

发布时间：2019-04-10 16:11

【摘要】：随着我国经济的迅速发展,大跨度斜拉桥大量兴建,其中斜拉索作为结构的重要构件,对桥梁安全起着至关重要的作用。现阶段研究表明,拉索这种阻尼小、垂度大、刚度小的特殊结构,在外界荷载作用极易发生大幅度的振动疲劳破坏,因此对斜拉索的减振研究显得尤为重要。目前用于拉索被动控制的方法有三种,包括空气动力学措施、构造措施和机械阻尼措施,其中粘滞阻尼器应用最为广泛,但大量实践表明:一般结构形式的粘滞阻尼器通常安装在斜拉索的端部,控制拉索的振动位移较小,并且与桥面梁相连接,在外荷载的作用下极易发生共振现象,其减振效果远低于理论值。不受安装位置影响的调谐质量阻尼器(Tuned Mass Damper,TMD)则可以很好地克服一般机械阻尼器的上述缺点,但普通结构形式的调谐质量阻尼器由于自身重力问题,导致其对拉索的控制效果并不是很理想。本文提出了一种用于桥梁拉索振动控制的新型椭圆形薄壁结构调谐质量阻尼器。该阻尼器采用多个椭圆形薄壁结构连接组成,具有结构构造简单、安装方便、不需外部设备控制、维护成本低等优点,并且该装置可以承担自身重量,因此可以方便地用于大跨度桥梁斜拉索和系杆等构件的振动控制。本文研究内容包括以下几个方面:(1)单个椭圆形薄壁结构力学性能研究。利用有限元软件,通过参数化建模,分析了单个椭圆形薄壁结构采用不同设计参数时的力学性能,通过拟合有限元软件得到的计算结果,建立单个椭圆形薄壁结构简化力学模型,获得最大屈服范围与参数之间的关系,并分析了单个椭圆形薄壁结构水平和竖向受力方向上的耦合作用。此外,利用能量法研究了单个椭圆形薄壁结构力与变形关系的近似计算方法,并通过数值模拟验证了该方法的有效性。(2)整个调谐质量阻尼器结构力学性能研究。将多个椭圆形薄壁结构进行有机组合,形成了用于索振动控制的调谐质量阻尼器。通过各个椭圆形薄壁结构空间几何相互关系以及自身力与变形的力学性能,研究了整个阻尼器力与变形关系,建立了整个阻尼器力学模型,研究结果表明阻尼器在不同振动方向上的力学性能变化不大,可以用于索多方向振动控制(3)基于新型阻尼器的索振动控制研究。本章分别从有限元模型和不考虑索抗弯刚度和垂度的简化模型,来研究本文提出的调谐质量阻尼器的减振效果。使用ANSYS软件建立椭圆薄壁结构TMD—拉索模型,分析其减振效果;采用时程分析的方法,求解椭圆薄壁结构TMD—拉索系统在随机风荷载作用下的减振效果;用适当的方法将非线性椭圆薄壁结TMD线性化,并验证其可行性。结果表明:在误差可接受的范围内,线性后与原非线性结构相比,减振效果相当。模拟结果显示本文所设计的椭圆形薄壁结构调谐质量阻尼器对斜拉索具有很好的抑制效果。
[Abstract]:With the rapid development of economy in China, a large number of long-span cable-stayed bridges have been built. Cable-stayed cables, as an important component of the structure, play an important role in the safety of bridges. At present, the research shows that this special structure, which has small damping, large sag and small stiffness, is prone to a great deal of vibration fatigue failure under external load, so it is very important to study the vibration reduction of cable-stayed cables. At present, there are three methods for passive control of cables, including aerodynamic measures, structural measures and mechanical damping measures, among which viscous dampers are the most widely used. However, a lot of practice shows that the viscous damper of general structure is usually installed at the end of stay cable, and the vibration displacement of control cable is small, and connected with bridge deck beam, it is easy to occur resonance phenomenon under the action of external load. Its damping effect is much lower than the theoretical value. The tuned mass damper (Tuned Mass Damper,TMD), which is not affected by the installation position, can overcome the above shortcomings of the general mechanical damper, but the tuned mass damper of the ordinary structure is due to its own gravity problem. Leading to its control effect on the cable is not very ideal. A novel tuned mass damper for bridge cable vibration control is presented in this paper. The damper is composed of several elliptical thin-walled structures, which has the advantages of simple structure, convenient installation, no control of external equipment, low maintenance cost and so on. The device can bear its own weight, and the device has the advantages of simple structure, convenient installation, low maintenance cost and so on. Therefore, it can be used to control the vibration of stayed cables and tie members of long-span bridges. The main contents of this paper are as follows: (1) the mechanical properties of a single elliptical thin-walled structure are studied. By using the finite element software and parametric modeling, the mechanical properties of a single elliptical thin-walled structure with different design parameters are analyzed, and the calculated results are obtained by fitting the finite element software. A simplified mechanical model of a single elliptical thin-walled structure is established and the relationship between the maximum yield range and the parameters is obtained. The coupling between horizontal and vertical stress directions of a single elliptical thin-walled structure is analyzed. In addition, the energy method is used to study the approximate calculation method of the force-deformation relation of a single elliptical thin-walled structure, and the effectiveness of the method is verified by numerical simulation. (2) the mechanical properties of the whole tuned mass damper structure are studied. A tuned mass damper (TMD) for cable vibration control is formed by organically combining several elliptical thin-walled structures. In this paper, the relationship between force and deformation of the dampers is studied and the mechanical model of the dampers is established by means of the spatial geometric relationship of each elliptical thin-walled structure and the mechanical properties of the self-force and deformation. The results show that the mechanical properties of the damper vary little in different vibration directions and can be used in multi-direction vibration control of cable (3) the vibration control of cable based on the new damper. In this chapter, the damping effect of the tuned mass damper proposed in this paper is studied from the finite element model and the simplified model without considering the flexural stiffness and sag of the cable. The TMD- cable model of elliptical thin-walled structure is established by using ANSYS software, and its damping effect is analyzed, and the damping effect of TMD- cable system of elliptical thin-walled structure under random wind load is solved by time-history analysis method. The nonlinear elliptic thin wall junction (TMD) is linearized by a suitable method, and the feasibility of the linearization is verified. The results show that, in the acceptable range of error, the damping effect of linear post-structure is similar to that of the original nonlinear structure. The simulation results show that the tuned mass dampers of elliptical thin-walled structures designed in this paper have a good suppression effect on cable-stayed cables.
【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】：2017
【分类号】：U441.3

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