【摘要】：斜拉橋造型美觀、跨度大、適用性廣,近年來(lái)在國(guó)內(nèi)已經(jīng)得到廣泛應(yīng)用。但由于拉索柔度較大,自身固有阻尼極低,受到風(fēng)、雨和橋上車輛的作用,極易發(fā)生持續(xù)的大幅度振動(dòng)。隨著斜拉橋跨徑日漸增大,斜拉索減振成為斜拉橋設(shè)計(jì)及健康維護(hù)領(lǐng)域一項(xiàng)重要課題。目前斜拉索減振主要有以下幾類措施：附加減振阻尼器、安裝輔助索、改變拉索氣動(dòng)力參數(shù)、主動(dòng)(半主動(dòng))控制措施。其中附加減振阻尼器措施具有良好的通用性和有效性,在國(guó)內(nèi)得到廣泛采用。本文著重完善了兩類斜拉索減振阻尼器——外置式粘滯阻尼器及磁流變阻尼器的設(shè)計(jì)應(yīng)用研究。對(duì)于斜拉索外置式粘滯阻尼器,通過(guò)理論分析與簡(jiǎn)化,提出粘滯阻尼器簡(jiǎn)化設(shè)計(jì)方法。該方法利用四個(gè)分別表征抑振模態(tài)、阻尼器內(nèi)剛度影響、支撐剛度影響、拉索垂度影響的修正系數(shù),實(shí)現(xiàn)粘滯阻尼器的粘滯系數(shù)選擇及支撐剛度要求,并通過(guò)對(duì)實(shí)際斜拉索的參數(shù)統(tǒng)計(jì)給出了各修正系數(shù)的建議值。算例驗(yàn)證表明,簡(jiǎn)化設(shè)計(jì)方法得到的最優(yōu)粘滯系數(shù)與精確解偏差小于4.6%,拉索前三階模態(tài)阻尼比與最優(yōu)解偏差小于2.3%。對(duì)于磁流變阻尼器,本文基于DSP芯片研發(fā)了模態(tài)切換控制器�？刂破魍ㄟ^(guò)實(shí)時(shí)監(jiān)測(cè)拉索振動(dòng)加速度信號(hào),識(shí)別拉索首要振動(dòng)模態(tài),按照用戶設(shè)置值,向磁流變阻尼器輸出各階控制電流。該控制器被應(yīng)用于椒江二橋最長(zhǎng)拉索的減振。實(shí)驗(yàn)室檢測(cè)及現(xiàn)場(chǎng)試驗(yàn)表明,控制器能夠根據(jù)振動(dòng)模態(tài)準(zhǔn)確輸出對(duì)應(yīng)電流,具有減振效果好、成本低、穩(wěn)定可靠等優(yōu)點(diǎn),具有很好的工程推廣前景。
[Abstract]:The cable-stayed bridge has been widely used in China in recent years because of its beautiful shape, large span and wide applicability. However, because of the flexibility of cable, the inherent damping is extremely low, and is affected by wind, rain and vehicles on the bridge, it is easy to occur sustained large amplitude vibration. With the increasing span of cable-stayed bridges, cable-stayed cable vibration absorption has become an important subject in the field of design and health maintenance of cable-stayed bridges. At present, the main measures of cable vibration reduction are as follows: additional vibration damper, installation of auxiliary cable, change of cable aerodynamic parameters, active (semi-active) control measures. The additional dampers are widely used in China because of their good versatility and effectiveness. In this paper, the design and application of two kinds of cable dampers, external viscous dampers and magnetorheological dampers, are studied. Based on theoretical analysis and simplification, a simplified design method for external viscous dampers with stay cables is proposed. In this method, four modified coefficients of vibration suppression mode, internal stiffness of damper, stiffness of bracing, sag of cable are used to select the viscosity coefficient of viscous damper and the requirement of bracing stiffness. The suggested values of the correction coefficients are given through the statistics of the parameters of the actual stay cables. Numerical examples show that the deviation between the optimal viscosity coefficient and the exact solution obtained by the simplified design method is less than 4.6, and the first three order modal damping ratio and the optimal solution deviation of the cable are less than 2.3th order. For Mr damper, a mode switching controller based on DSP chip is developed. The controller detects the vibration acceleration signal of the cable in real time, identifies the main vibration mode of the cable, and outputs each order control current to the magnetorheological damper according to the value set by the user. The controller is applied to the vibration reduction of the longest cable of Jiaojiang second Bridge. The laboratory test and field test show that the controller can output the corresponding current accurately according to the vibration mode, which has the advantages of good vibration absorption effect, low cost, stability and reliability, and has a good prospect of engineering popularization.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U448.27

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本文編號(hào)：2278834