基于桥梁主梁断面气动导数、阶跃函数与气动导纳之间的关系,提出一种获取气动导纳的阶跃函数拟合法。首先根据紊流风场中的抖振响应,识别桥梁结构气动导数和等效气动导纳,然后由气动导数可拟合得到阶跃函数,并根据阶跃函数系数计算得到竖向脉动风对应的气动导纳,最后结合等效气动导纳计算水平向脉动风对应的气动导纳。阶跃函数拟合法直接根据抖振响应完成了桥梁断面完整气动导纳的识别,实例研究表明,该方法对于桥梁断面气动导纳识别而言是可行的。
Based on the relationships among flutter derivatives,indicial functions and aerodynamic admittance functions,a method is proposed for determining the complete aerodynamic admittance functions.First,the buffeting response of bridge decks in turbulent wind field,from which flutter derivatives and equivalent aerodynamic admittance functions can be estimated,is obtained.Then,indicial functions are calculated according to the relationships between flutter derivatives and indicial functions and aerodynamic admittance functions corresponding to vertical turbulent wind,which can be used to determine aerodynamic admittance functions corresponding to longitudinal turbulent wind if equivalent aerodynamic admittance functions is given,is determined on the basis of the relationships between indicial functions and aerodynamic admittance functions.The feasibility of the proposed method,by which the complete aerodynamic admittance functions of bridge decks can be estimated according to their buffeting response in turbulent wind field,is verified by wind tunnel tests for streamlined or bluff body models.