大跨度悬索桥颤振分析的能量方法

Flutter analysis of long-span suspension bridges by energy method

建立了对悬索桥进行颤振分析的一种新的计算方法。该方法将结构与气流作为一个系统 ,从能量平衡的角度研究系统的稳定性 ;将模态广义坐标位移和速度作为状态向量 ,首先组集系统在自激力作用下的状态空间方程 ,然后应用精细时程积分求解状态向量的时程响应 ,在此基础上计算系统及各阶模态的等效阻尼比 ,并由系统的等效阻尼比判断系统在不同风速下的稳定性 ;以跨度为888m的虎门悬索桥为算例 ,证实了本文方法的正确性。

A new computational method for analyzing the flutter of suspension bridges is described.The bridge structure is combined with wind as a whole system in the paper,and the flutter stability of the system is studied at the point of energy balance.The generalized coordinate displacements and velocities of the modes are taken as the state space vector.Firstly,the system's state space equation is assembled under the action of the self exited aerodynamic forces.Then,the time history of the state space vector is computed by the precise time integration method.Based on the state space vector's time history,equivalent damping ratios of the system and each mode is calculated,and the flutter stability of systems is judged by the equivalent damping ratio of the system at different wind speeds.Finally,the Humen Bridge,a suspension bridge with a steel box deck and a center span 888 m,is carried out to confirm the method.