大气湍流中的悬索桥颤振时域分析

综合考虑结构几何非线性、不同来流条件下气动力等因素对悬索桥气动稳定性的影响,利用风洞试验得到的颤振导数和对随机风场的时程模拟来计算桥梁的自激气动力和抖振力,对均匀流和大气湍流中大跨度悬索桥颤振问题进行了时域分析,结果与风洞试验结果基本一致,证明了本方法的可行性.分析表明:湍流将降低大跨度流线形主梁断面悬索桥的颤振稳定性;计算自激气动力时应当考虑随时间和空间随机变化的脉动风速的影响.

Flutter analysis in time domain for long span suspension bridge in atmospheric turbulent flow

Based on time domain motion-excited force and buffeting force models, a flutter analysis method in time domain for a suspension bridge is presented by fully considering the structure's geometric nonlinearity and various flow conditions. This paper makes flutter analysis for two long span suspension bridges. The agreement between the analytical results and the wind tunnel test suggests that the method can be used to predict the flutter of long span bridge. Flutter in turbulent flow is also calculated, the results show that the effect of buffeting on critical wind speed of flutter can not be ignored, it will decrease the long span suspension bridge's aerodynamic stability with streamline cross section. In the computation of motion-excited force, the fluctuating wind which was ignored before, should be considered, and the analytical result is more close to the wind tunnel test result. The atmospheric turbulent flow's effect to the flutter of suspension bridge is shown not only on producing buffeting force, but also on affecting motion-excited force directly.