斜拉索是斜拉桥的关键受力构件，其自身阻尼很小因而易在环境激励下发生振动，危及斜拉桥的安全。在索近锚固点安装减振器是最有效的减振方法。为了研究实际索减振器的非线性行为并利用其在拉索减振中的优势，本项目拟研究斜拉索-非线性减振系统的动力特性及参数优化方法，将关注该系统的重要动力特性--稳态响应。首先，拟引入近来在机械等领域快速发展、能高效求解强非线性系统的谐波平衡法，研究该方法在分析索减振系统这一多自由度结构中的适用性；进而，研究基于系统稳态动力特性评价其减振性能的合理方法；最终，建立基于谐波平衡法的拉索-非线性减振系统的动力分析及参数优化框架。拟利用该方法，具体分析非线性粘滞阻尼器、摩擦阻尼器及限位装置安装于索近锚固点时对索前几阶振动的最优控制效果及相应装置参数，探讨非线性减振机理。本课题的成果将直接应用于拉索减振装置的优化设计，为索减振方案的开发提供理论基础，具有明确的工程和理论价值。

Stay cables, as significant structural members in cable-stayed bridges, are vulnerable to ambient excitations owing to its extremely low inherent damping, posing a threat to the bridge safety. Installing near-anchorage damper is among the most effective countermeasures for cable vibration control. To include the nonlinearity of real-world dampers and further explore the advantage of nonlinear control for improving cable vibration mitigation, this project intends to conduct dynamic analysis and parameter optimization of a cable attached with a nonlinear control device. Firstly, steady-state responses, which represent a significant subset of the dynamics of a nonlinear system, will be focused on for the concerning system; harmonic balance method (HBM) which is undergoing rapid development in fields such as mechanical engineering and capable of efficiently handling strong nonlinearity, will be introduced and accommodated to deal with the multi-degree-of-freedom cable systems. Secondly, research effort will be dedicated to the development of appropriate approaches for appreciating the control effect of the nonlinear device based on system steady-state responses. Eventually, a HBM-based methodology will be established for dynamic analysis and parameter optimization of the cable under nonlinear control. Furthermore, using this method, typical nonlinear devices including nonlinear viscous damper, friction damper and lateral contactor will be analyzed in detail for maximizing cable vibration control effect; nonlinear control mechanism will be revealed meanwhile. The results of this project can be directly used for cable vibration control design and provide a theoretical framework for exploring new control schemes. In other words, this project is of both practical and theoretical significance.