超大跨度悬索桥二维颤振频域直接分析方法

Straight forward method for two-dimensional flutter analysis of super-long-span suspension bridge in frequency domain

为改善传统复模态特征值分析方法(CEVA)求解二维颤振问题时迭代不收敛和运算时间较长的问题,基于传统复模态特征值分析方法和费拉里求解一元四次方程的思路,提出了二维颤振频域直接分析方法(Straight forward method),在超大跨度悬索桥二维颤振分析中无需频率的预先选取和迭代求解,计算时间短.采用该方法对闭口钢箱梁、理想平板、中央开槽钢箱梁、中央双开槽钢箱梁这4种典型断面各6种跨度的悬索桥进行二维颤振频域直接分析.结果表明:从颤振稳定性能的要求出发,跨度小于1500m的悬索桥可采用闭口钢箱梁,跨度小于3000m的悬索桥需采用单开槽钢箱梁,跨度大于3000m的悬索桥需采用双开槽钢箱梁.

The conventional eigen value analysis method（CEVA）has some shortcomings in solving two-di-mensional coupled flutter problems,for example,when the frequency ratio of torsional to bending is approac-hing 1,the pre-selection of frequency and its iteration is a time consuming work.This paper presents an straight forward method for analyzing two-dimensional coupled flutter of super-long-span suspension bridges,u-tilizing CEVA method and Ferrari＇s thoughts on solving univariate equations of four degrees,which has both improvements on work process and work time compared with the CEVA method.Case studies of four different cross section suspension bridges（the ideal plate,close steel box,single slotted steel box,and double slotted steel box）are provided to validate the developed procedure as well as to demonstrate the flutter analysis of su-per-long-span suspension bridges using straight forward method.The proposed method in this paper enables the researchers to make comparison on the flutter modality,flutter stability performance and freedom coupling extent of suspension bridges with different mid-span and different cross sections.