对桥梁抖振的分析传统上均采用单模态叠加SRSS法,但随着桥梁的长大化,模态间气动耦合效应的影响越来越大,在分析中必须加以考虑.有鉴于此,文中采用Scanlan多模态耦合抖振理论,以2自由度弯扭耦合系统为研究对象,通过定义系统的10种不同的传递函数并考察系统传递函数随风速的变化规律,对模态间气动耦合效应进行进一步的研究,揭示了模态间气动耦合的机理和本质. Traditionally, single-modal superposition of SRSS is used to analyze the chattering of bridge, but as the bridge grows, the influence of the aerodynamic coupling effect between modalities becomes more and more important and must be considered in the analysis.In view of this, In this paper, Scanlan multi-mode coupled chattering theory is used to study the 2-degree-of-freedom torsional-torsional coupling system. By defining 10 different transfer functions of the system and investigating the variation of the system transfer function with wind speed, The coupling effect is further studied and the mechanism and essence of aerodynamic coupling between modes are revealed.