附加攻角效应对颤振稳定性能影响

用强迫振动装置识别攻角从-3°~+4°细化步长变化为1°的洞庭湖二桥主梁断面气动导数;将该气动导数拟合成折减风速、攻角的三维曲面,只需获取某一有效攻角的具体数值即可自动求得所有气动导数值。通过在ANSYS中的三维TABLE表存储各攻角的气动导数,自动计入附加攻角对颤振稳定性影响。全模态颤振分析结果表明,附加攻角效应可降低该类桥梁的颤振临界风速。若按常规试验方法以3°攻角为步长进行气动导数插值计算,颤振分析有可能得到错误结论。

Influence of static wind additive attack angle on flutter performance of bridges

Aerodynamic derivatives of Dongting Lake Bridge Girder Sections were identified by forced vibration in wind tunnel, and the angle of attack changes in steps of 1 ° from -3 ° to +4 °. the aerodynamic derivatives were fitted to three-dimensional surface by reduced velocity,angle of attack. Just to obtain a specific value of the effective angle of attack, all aerodynamic derivatives can be automatically obtained by the value of each angle of attack. aerodynamic derivatives were stored by three-dimensional TABLE in ANSYS, The effect of additional angle of attack to flutter stability were automatically included. Full-mode flutter analysis indicated that the additional angle of attack effect reducing typical bridge critical flutter speed, influence extent due to the different type of bridge.