本文選題：振動控制 + 輔助索　； 參考：《重慶交通大學(xué)》2015年碩士論文

【摘要】：隨著經(jīng)濟發(fā)展和科學(xué)的進步,橋梁朝著大跨度方向發(fā)展,斜拉橋在現(xiàn)代交通體系中起著日益重要的作用,而斜拉索則是斜拉橋中最主要的受力構(gòu)件。由于斜拉索具有質(zhì)量輕、阻尼低、柔度大等特點,極易在外界的激勵下產(chǎn)生各種類型的有害振動。斜拉索的振動會引起拉索錨固端的疲勞損傷甚至破壞,從而影響橋梁的正常使用,因此如何有效的對斜拉索的振動進行控制是橋梁動力學(xué)目前最重要的課題之一。斜拉索常用的制振措施有：傳統(tǒng)的氣動措施、設(shè)置集中阻尼器、設(shè)置輔助索。輔助索將斜拉索分成若干段,從而提高了斜拉索剛度。同時將空間結(jié)構(gòu)上獨立的斜拉索連接形成索網(wǎng)體系,提高了索面的整體剛度。設(shè)置輔助索不能提高索網(wǎng)體系的耗能能力,制振效果仍受一定限制。在輔助索端或輔助索與斜拉索連接處安裝集中阻尼能提高索網(wǎng)體系的阻尼,從而使其減振效果顯著提高。斜拉索-輔助索索網(wǎng)體系的減振機理仍缺乏可靠的理論依據(jù),特別是在參數(shù)的選取及優(yōu)化方面還不完善。本文通過理論分析和有限元仿真相結(jié)合的方法分析了輔助索參數(shù)的選取,及輔助索不同參數(shù)對斜拉索-輔助索索網(wǎng)體系制振效果的影響規(guī)律,研究了集中阻尼器類型的選擇和位置的選取及優(yōu)化。本文以水土嘉陵江大橋跨中斜拉索為研究背景,首先對單根斜拉索進行靜力及動力特性分析。確立了單根拉索的理論模型,并建立了合理的有限元仿真模型。利用有限元軟件ANSYS對單根拉索的動力特性進行仿真分析�？紤]斜拉索垂度效應(yīng)和阻尼效應(yīng)等因素對拉索各階模態(tài)的頻率、阻尼比、振形的影響效果。其次對輔助索的減振機理進行理論研究,通過有限元仿真模型分析輔助索的張拉方式、安裝點位、截面面積、初始張拉力等參數(shù)對索網(wǎng)結(jié)構(gòu)動力特性的影響規(guī)律。接著建立索網(wǎng)體系的自由振動方程,并結(jié)合邊界方程、變形協(xié)調(diào)方程和力的平衡方程得到系統(tǒng)的振動模態(tài)。利用近似解析式研究索網(wǎng)的整體剛度和阻尼器的剛度對系統(tǒng)模態(tài)頻率和阻尼比的影響。提出兩種可用于索網(wǎng)減振的集中阻尼器,并確定阻尼器的布置方案。通過ANSYS軟件建立仿真模型,用復(fù)模態(tài)分析方法得出設(shè)置兩種阻尼器時索網(wǎng)結(jié)構(gòu)的模態(tài)參數(shù)。對比所得模態(tài)頻率和模態(tài)阻尼比,以兩種模態(tài)參數(shù)分析兩種不同方式阻尼器的制振效果。最后以模態(tài)阻尼比和模態(tài)頻率作為指標(biāo)提出阻尼器的優(yōu)化思路。
[Abstract]:With the development of economy and science, the bridge is developing towards the direction of large span. The cable-stayed bridge plays an increasingly important role in the modern traffic system, and the cable-stayed cable is the most important component of the cable-stayed bridge. Because the cable-stayed rigging has the characteristics of light weight, low damping and large flexibility, it is easy to produce various kinds of harmful vibration under external excitation. The vibration of cable will cause fatigue damage or even damage of cable anchoring end, which will affect the normal use of bridges. Therefore, how to effectively control the vibration of stay cables is one of the most important issues in bridge dynamics. The commonly used vibration control measures for stay cables are: traditional pneumatic measures, centralized dampers and auxiliary cables. The auxiliary cable divides the stay cable into several sections, thus improving the stiffness of the stay cable. At the same time, the cable-net system is formed by connecting the independent cable-stayed cables in the spatial structure, which improves the overall stiffness of the cable-plane. The setting of auxiliary cable can not improve the energy dissipation ability of cable net system, and the vibration control effect is still limited to some extent. Installing concentrated damping at the auxiliary cable end or at the connection between the auxiliary cable and the stay cable can increase the damping of the cable-net system, so that the damping effect of the cable net system can be greatly improved. The vibration absorption mechanism of cable-assisted cable-net system is still lack of reliable theoretical basis, especially in the selection and optimization of parameters is not perfect. In this paper, the selection of auxiliary cable parameters and the influence of different auxiliary cable parameters on the vibration control effect of cable-assisted cable-net system are analyzed by means of theoretical analysis and finite element simulation. The selection of the type of concentrated damper and the selection and optimization of location are studied. In this paper, the static and dynamic characteristics of single cable are analyzed based on the research background of the middle stay cable of Jialing River Bridge. The theoretical model of single cable is established, and a reasonable finite element simulation model is established. The finite element software ANSYS is used to simulate and analyze the dynamic characteristics of single cable. The effects of cable sag effect and damping effect on the frequency, damping ratio and vibration shape of cable are considered. Secondly, the vibration absorption mechanism of auxiliary cable is studied theoretically, and the influence of the parameters such as tension mode, installation point, cross-section area and initial tension on the dynamic characteristics of cable net structure is analyzed by finite element simulation model. Then the free vibration equation of cable-net system is established, and the vibration modes of the system are obtained by combining the boundary equation, the deformation coordination equation and the equilibrium equation of the force. The effects of the overall stiffness of the cable net and the stiffness of the damper on the modal frequency and damping ratio of the system are studied by using the approximate analytical formula. Two kinds of concentrated dampers which can be used to reduce the vibration of cable-net are proposed and the layout of dampers is determined. The simulation model is established by ANSYS software, and the modal parameters of cable-net structure with two dampers are obtained by using complex modal analysis method. Compared with the modal frequency and the modal damping ratio, the vibration suppression effects of two different dampers are analyzed with two modal parameters. Finally, the optimization idea of damper is put forward with modal damping ratio and modal frequency as indicators.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U441.3;U448.27

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本文編號：2045688