【摘要】：斜拉橋結(jié)構(gòu)阻尼低、柔度大,在地震荷載作用下會導(dǎo)致上部結(jié)構(gòu)的大幅振動,易在關(guān)鍵部位產(chǎn)生大的內(nèi)力而使結(jié)構(gòu)破壞失效,因此需要采取安裝TMD(tuned mass dampers)等措施進(jìn)行減震。作為大型空間柔性結(jié)構(gòu),斜拉橋具有復(fù)雜的靜動力特性,往往表現(xiàn)出主頻低,模態(tài)密集的特性。因此,需要采用分布式TMD以實(shí)現(xiàn)對結(jié)構(gòu)的多階模態(tài)振動減震,進(jìn)而通過合理的方法來實(shí)現(xiàn)多TMD的配置和參數(shù)優(yōu)化。 本文在總結(jié)國內(nèi)外結(jié)構(gòu)振動控制及斜拉橋減震的基礎(chǔ)上,探討用基于模態(tài)坐標(biāo)表示的H2范數(shù)指標(biāo)實(shí)現(xiàn)斜拉橋減震的TMD的配置優(yōu)化,以及基于H2性能的梯度優(yōu)化法實(shí)現(xiàn)分布式TMD的參數(shù)優(yōu)化,并對減震效果進(jìn)行分析。主要研究工作如下： 1.用基于模態(tài)坐標(biāo)表示的H2范數(shù),建立考慮了外界激勵影響的針對TMD配置優(yōu)化的指標(biāo),提供了一種能夠?qū)崿F(xiàn)定量分析TMD配置數(shù)量和位置的方法；建立分布式TMD對地震激勵下多自由度結(jié)構(gòu)實(shí)現(xiàn)多模態(tài)減震的力學(xué)模型,并表達(dá)為閉環(huán)靜力反饋控制的形式,研究了具有較高優(yōu)化效率的基于H2性能的梯度優(yōu)化法,實(shí)現(xiàn)了對多模態(tài)調(diào)諧減震的TMD的參數(shù)同步整體優(yōu)化。 2.以構(gòu)建的理想三自由度密頻結(jié)構(gòu)為例,進(jìn)行分布式TMD的優(yōu)化設(shè)計(jì)。引入以控制輸出分量表示的無量綱評價指標(biāo),優(yōu)化得到了具有相對普適性的控制輸出權(quán)重,進(jìn)而利用基于H2性能的梯度優(yōu)化法實(shí)現(xiàn)了TMD的參數(shù)優(yōu)化。經(jīng)過與經(jīng)典TMD優(yōu)化方法的對比,驗(yàn)證了基于H2性能的梯度優(yōu)化法優(yōu)化所得的TMD在針對多模態(tài)密頻結(jié)構(gòu)減震時具有更好的性能。 3.分別針對斜拉橋施工狀態(tài)及成橋狀態(tài),建立了用于控制設(shè)計(jì)的結(jié)構(gòu)模型,對斜拉橋結(jié)構(gòu)動力特性和響應(yīng)特征進(jìn)行分析。利用基于H2范數(shù)的配置指標(biāo)定量分析了TMD最優(yōu)安裝位置和數(shù)量,結(jié)果表明通過該指標(biāo)配置的TMD數(shù)量和位置更具敏感性,并考慮了外激勵的影響,達(dá)到了更好的TMD配置效果；利用基于H2性能的梯度優(yōu)化法和經(jīng)典方法優(yōu)化了配置的TMD的參數(shù),多個角度評價和分析了不同地震波輸入時兩種方法TMD的減震效果,結(jié)果表明利用基于H2性能的梯度優(yōu)化法優(yōu)化的TMD對頻率密集的斜拉橋結(jié)構(gòu)能夠取得更好的減震效果。
[Abstract]:The structure of cable-stayed bridge has low damping and large flexibility, which will lead to large vibration of superstructure under earthquake load, and it is easy to produce large internal force in the key position and make the structure failure. Therefore, it is necessary to take measures such as installing TMD (tuned mass dampers) to reduce the vibration. As a large space flexible structure, cable-stayed bridges have complex static and dynamic characteristics, which often show low main frequency and dense modes. Therefore, it is necessary to adopt distributed TMD to achieve multi-modal vibration damping of the structure, and then to realize the configuration and parameter optimization of multi-TMD by reasonable methods. On the basis of summing up the vibration control of structures at home and abroad and the damping of cable-stayed bridges, this paper discusses how to optimize the configuration of TMD for cable-stayed bridges by H _ 2 norm index based on modal coordinate representation. The parameter optimization of distributed TMD is realized by gradient optimization method based on H2 performance, and the effect of damping is analyzed. The main research work is as follows: 1. Based on the H _ 2 norm expressed by modal coordinates, the optimization index for TMD configuration considering the influence of external excitation is established, and a method to quantitatively analyze the quantity and position of TMD configuration is provided. In this paper, a mechanical model of distributed TMD is established to achieve multi-mode vibration absorption of multi-degree-of-freedom structures under earthquake excitation, which is expressed as closed-loop static feedback control. A gradient optimization method based on H _ 2 performance with high optimization efficiency is studied. The parameter synchronization optimization of multimodal tuned TMD is realized. 2. Taking the ideal three degree of freedom dense frequency structure as an example, the optimal design of distributed TMD is carried out. The dimensionless evaluation index expressed by the control output component is introduced to optimize the control output weight with relative universality and then the parameter optimization of TMD is realized by using the gradient optimization method based on H2 performance. By comparing with the classical TMD optimization method, it is verified that the TMD obtained by gradient optimization based on H2 performance has better performance for multi-modal dense frequency structure. 3. According to the construction state and the completed state of cable-stayed bridge, the structural model for control design is established, and the dynamic characteristics and response characteristics of cable-stayed bridge are analyzed. The optimal installation location and quantity of TMD are quantitatively analyzed by using the allocation index based on H 2 norm. The results show that the number and position of TMD configured by this index is more sensitive, and the effect of external excitation is considered, which can achieve a better TMD configuration effect. The parameters of the configured TMD are optimized by using the gradient optimization method based on the H2 performance and the classical method. The seismic absorption effects of the two methods for different seismic wave input are evaluated and analyzed from several angles. The results show that the TMD optimized by gradient optimization method based on H _ 2 performance can achieve better damping effect on the cable-stayed bridge structures with dense frequencies.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441.3;U448.27

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