阻尼器-索支撑体系耦合动力学机制及复杂行为研究

大跨度斜拉桥拉索大幅振动一直是工程和力学领域的热点研究问题。虽有多种类型的阻尼器被用于斜拉索的振动控制，但在风雨荷载作用下众多斜拉桥上仍然观测到了振幅高达1米的拉索振动。目前对阻尼器-斜拉索耦合结构体系产生这种大幅振动的内在动力学机制尚不清楚。目前的研究中存在两个问题：一是工程界对阻尼器的设计大多针对斜拉索的特定模态，即使考虑多模态振动问题，也是基于叠加原理的线性分析，缺少对结构非线性振动机理的认识；二是力学领域对斜拉桥结构的复杂动力学行为虽有广泛研究，但均依赖于一个重要假设，即使用模态阻尼替代阻尼器，没有将阻尼器作为结构中的单元进行系统研究。因此，本项目拟从耦合动力学角度，建立斜拉桥索支撑体系的多索-阻尼器-浅拱(梁)非线性动力学模型，揭示有阻尼器参与的索支撑体系模态耦合动力学行为和机理，特别是阻尼器的能量传递与耗散机制，并开展相应的实验验证，为斜拉索的有效减振奠定理论基础。

The large-scale vibration of cables for long-span cable-stayed bridges has been a hot issue in the field of civil engineering and mechanics. Although many types of dampers have been used to control vibrations of cables, their vibrations with amplitudes up to 1 m are still observed on many cable-stayed bridges under wind and rain loads. At present, the internal dynamic mechanism triggering the large-scale vibrations of cables in the damper-cable coupling structure system is still unclear. There are two problems in previous work. Firstly, most of dampers are designed for vibration suppression of a special mode of cables. Even considering a multi-modal vibration problem, they are based on linear analysis of superposition principle and lack knowledge of non-linear vibration behavior of structures. Secondly, although the complex dynamic behavior of cable-stayed bridges has been extensively studied in the field of mechanics, they all depend on an important assumption that modal damping can be used to replace the damper; hence, there is no work that the damper-cable coupling structure system is systematically studied with consideration of damper. Therefore, from the perspective of coupling dynamics, the project intends to establish a multi-cable-damper-shallow arch (beam) nonlinear dynamic model of cable support system of cable-stayed bridge, and reveals the modal coupling dynamic behavior and its mechanism of cable-supported system with dampers, especially the energy transfer and dissipation mechanism of dampers, and the corresponding experimental verification is carried out, which can lay a theoretical foundation for effective vibration reduction of cable-stayed bridges.