【作者】 付英；

【导师】 刘红军；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2009， 硕士

【摘要】 斜拉索是斜拉桥中的主要承重结构,它具有阻尼小、柔度大、质量轻的特点,极易在地震激励、风致激励和动载激励等作用下产生大幅振动,影响桥梁结构的安全、使用性能与寿命,因而有必要对拉索的振动采取一定的控制措施。当荷载作用于桥梁结构时,桥面和桥塔会按一定频率振动,而拉索的两端分别与桥面和桥塔相连,因而桥面和桥塔的振动为拉索施加了运动的边界条件,带来一定的基础激励。通过分析基础激励作用下拉索的振动机理可以在实践中避免并减小拉索的大幅振动,防止桥梁结构的破坏。在拉索近锚固端安装阻尼器可以提高拉索系统的等效阻尼比,消耗外界的输入的能量,有效控制拉索的振动。其中,磁流变阻尼器是由智能材料组成的可调参数阻尼器,通过调节外加的直流电压来选取不同的阻尼系数,从而很好地控制桥梁斜拉索的大幅振动,在土木工程中具有广泛的应用前景。本文运用有限元软件ANSYS建立了斜拉桥(深圳湾公路大桥)的力学模型,通过对其进行仿真模拟,得出了斜拉桥在地震、车辆、风等荷载作用下桥面及桥塔上最长拉索锚固点的振动响应,将比较得出的最不利荷载施加于单根斜拉索上,从而更加真实地模拟了斜拉索在基础激励下的振动反应特性,并在此基础上研究了斜拉索的谐波共振和参数共振这两种大幅振动,讨论了各种内部和外部因素对以上两种拉索共振的影响。其中的影响参数包括:位移激励幅值、初始索力、模态阻尼比及拉索倾角。最后,本文通过模拟斜拉索与磁流变阻尼器共同组成的振动控制系统,介绍了磁流变阻尼器的工作原理及力学模型,研究了其对拉索的振动控制机理及特性,进一步探讨了阻尼力大小、阻尼器位置、激振力幅值及初始索力等相关参数对振动控制系统减振效果的影响,通过优化相关参数,可以使磁流变阻尼器达到最优的减振效果。更多还原

【Abstract】 Cable-Stayed is the main load-bearing components in cable-stayed structure. It is vulnerable to generate significant vibration under the incentives such as the seismic, wind, and vehicle loading because of the characteristics of low damping, great flexibility and light weight. So it will affect the safety, performance and life expectancy of bridge structures. And it is necessary to take vibration control measurement for the cables. When the load acting on the bridge structure, the bridge deck and the bridge towers will have a certain frequency of vibration, and the two ends of cable are connected to the bridge deck and the bridge towers respectively, so the vibration of bridge deck and towers impose the boundary conditions for cable movement, which is certain foundation incentive. By analyzing the vibration mechanism under foundation excitation for cable, we will avoid and reduce the significantly vibration of the cable in practice. and prevent the destruction of the bridge structure. To install damper near the end of anchor will improve equivalent damping ratio of the cable-stayed system, consumption of external energy, and then effectively control the vibration of cables. Magneto-Rheological damper has a wide range of applications in civil engineering, since the MR damper can select different damping coefficient by adjusting the DC voltage applied. Thus it will control the great vibration in cable-stayed bridge perfectly.This thesis establishes a mechanical model of a cable-stayed bridge (Shenzhen Bay Bridge) with the finite element software ANSYS. Then simulate the seismic, wind, vehicle loading and other loads. Obtaining the maximum response of vibration at the deck and tower anchorage points with the longest cable in the bridge, as the displacement load imposed on the cable-stayed and thus more truly simulate the vibration characteristics of the cable under the foundation excitation. And on this basis to study two substantial vibration of harmonic resonance and parametric vibration, then analyze different influencing factors of these two kinds of vibration. The impact of parameters which include: excitation amplitude of displacement, the initial cable force, modal damping ratio, and the cable angle. Finally, by simulating cable-damper control system, this thesis analyze the control mechanism and features of MR damper in vibration control system, and to further study the relevant parameters which effect the cable-MR damper control system. These parameters include: the damping force, damper position, excitation amplitude and the initial cable force. By optimizing the relevant parameters, the MR damper will attend the Optimal damping effect.更多还原