大跨度悬索桥非线性颤振稳定性及气动控制措施研究

With the further development of transportation infrastructure construction, the construction of some infrastructure projects crossing river and sea will be the focus of the future transportation infrastructure construction.The basic wind speeds of the bridges in the coastal area are higher, and the wind-induced effects on the bridges have gradually become the control factor of the these large span bridges. The research results show that the vibration response of the large span bridges in the vicinity of the critical flutter state is limited to the limit cycle oscillation, which has obvious nonlinear characteristics.The research on the nonlinear self-excited aerodynamic forces and the post flutter state of the bridge girder sections has become one of the hot topics in the field of wind engineering of bridges in recent years. The study on nonlinear flutter stability and aerodynamic control measures of flutter stability of large span suspension bridges will be conducted in present project based on the Lingding bridge of the link project between Shenzhen with Zhongshan. Wind tunnel tests and numerical simulations are used to study unsteady aerodynamic forces characteristics and wind-induced vibration responses of typical girder sections under large amplitudes, large attack angles and turbulent flow separately. The nonlinear unsteady aerodynamic forces model of the bridge decks will be established by combining the nonlinear unsteady aerodynamic force model ROM and CFD numerical simulations. Considering the nonlinear factors such as large amplitudes and large attack angles, the experimental and numerical simulation methods are used to study the effects and mechanism of the aerodynamic control measures of flutter stability of the streamlined girder section.

随着交通基础设施建设的进一步推进，跨江、跨海工程建设将是未来一段时期交通基础设施建设的重点。沿海地区桥位基本风速较高，风对桥梁的作用已逐渐成为沿海地区大跨度桥梁设计的控制因素。研究表明大跨度桥梁在颤振临界状态附近主梁断面振动响应在有些情况下表现为极限环振动，具有明显的非线性特征。桥梁主梁断面非线性自激气动力与后颤振状态研究逐渐成为近年来桥梁风工程领域研究的热点问题之一。本项目以拟建的深中通道工程伶仃航道桥为依托，进行大跨度悬索桥非线性颤振稳定性及气动控制措施研究。采用风洞试验和数值模拟相结合的方法进行大振幅、大攻角以及紊流条件下典型主梁断面非定常气动力特性和风振响应特性研究；采用非线性非定常气动力降阶模型ROM与CFD数值模拟相结合的方法，建立主梁非线性非定常气动力模型；考虑大振幅、大攻角等非线性因素，采用试验与数值模拟方法进行流线型主梁断面颤振稳定性气动控制措施效果与机理研究。

随着国家交通强国战略的实施与交通基础设施建设的进一步推进，跨江、跨海交通基础设施建设将是未来一段时期的重点。我国沿海地区经济发达，对交通基础设施建设的需求巨大，而沿海地区又属于台风多发区，超大跨度桥梁抗风设计是沿海地区大跨桥梁抗风设计的关键性控制因素。.本课题采用理论分析、风洞试验和CFD数值模拟相结合的方法，针对超大跨度桥梁非线性颤振稳定性及气动控制措施，开展了如下研究：（1）大振幅条件下主梁非定常气动力和风振响应特性研究；（2）大攻角条件下典型断面的颤振特性研究；（3）紊流条件下主梁非定常气动力和风振响应特性研究；（4）主梁断面非线性非定常气动力模型研究；（5）流线型箱梁断面颤振稳定性改善气动措施及机理研究。取得如下主要成果：（1）获得了闭口流线型箱梁与桁架加劲梁非线性颤振响应特征，研究发现两类断面在某些攻角下存在明显的极限环振动现象，即弯扭耦合单频、振幅恒定的非线性振动现象；（2）获得了大攻角下薄平板断面、闭口流线型主梁断面气动力、颤振响应特征、气动导数及颤振临界风速随攻角的变化规律；（3）采用谐波合成法结合Fluent UDF编程实现了脉动风场CFD数值模拟，为开展主梁断面非线性颤振稳定性的紊流风效应奠定了基础；（4）采用Taylor级数展开多项式考虑主梁断面气动力高阶谐波成分，建立了大攻角条件下主梁断面非线性气动力模型；采用幅变气动导数建立了大振幅条件下主梁断面非线性气动力模型；基于Volterra级数建立了薄平板断面的非线性气动力降阶模型；（5）开展了流线型箱梁断面颤振稳定性气动优化措施与机理研究，获得了流线型主梁断面宽高比、风嘴角度以及中央稳定板高度对桥梁颤振临界风速的影响规律，揭示了设置中央稳定板提高桥梁颤振临界风速的机理。.课题研究成果已应用于深中通道工程伶仃洋大桥（主跨1666m悬索桥）、贵州瓮开高速公路开州湖特大桥（主跨1100m悬索桥）抗风设计中，为大桥的建设提供了技术支撑。本课题研究成果对于超大跨度缆索承重桥梁抗风设计具有重要的价值。