摘要
针对大跨度斜拉桥拉索与桥塔、桥面的协同振动问题,考虑拉索垂度、阻尼、倾角以及重力弦向分力的影响,引入拉索高精度抛物线形,建立了桥塔-索-桥面连续非线性精细化振动模型,推导了桥塔和桥面共同激励作用下斜拉索耦合振动方程,对比分析了2种激振模式下斜拉索的参数振动特性,并编制程序研究了桥面与拉索的频率比、桥面激励幅值、索力及阻尼对结构耦合振动特性的影响规律.结果表明:桥面与拉索频率比对系统振动的影响较大,频率比为1∶2和2∶1时拉索均产生强烈振动,但2∶1激振模式下拉索振幅更大,达到共振时间较长;随着桥面激励幅值的增大,2∶1亚谐波共振模式下的拉索振幅增长速率更快;拉索振幅随索力的增大呈非线性减小趋势;斜拉索阻尼超过2%时,继续提高自身阻尼不能有效减小其振动幅值,需要通过设置附加阻尼才能更好地抑制其振动.
In order to analyze coupled vibration of tower-cable-deck of long-span cable-stayed bridge under end excitation,the high precision parabola was specially introduced,with the cable sag,cable angle,cable damping and the tangential component of gravity along the cable being considered.Then a refined coupled vibration model of tower-cable-deck was established and the nonlinear vibration differential equation of tower-cable-deck under end excitation was obtained.The vibration characteristics of cable under different modes was compared with each other.The effects of the frequency ratio of cable to deck,deck excitation amplitude,cable force,damping and angle on the vibration of tower-cable-deck were carefully analyzed.The results showed that the frequency ratio of cable to deck had larger influence on cable vibration.The vibration of cable is very strong when the frequency ratio is 2∶1or 1∶2,but the amplitude of cable under 2：1vibration mode is larger and has longer resonance time than that under 1：2vibration mode.With the increase of the deck excitation amplitude,the amplitude growth rate under 2∶1vibration mode is faster.The cable amplitude decreases with the cable force increasing.When the cable damping is over 2%,the vibration amplitude of cable cannot be effectively reduced,and the vibration of the cable can be suppressed by setting additional damping.
出处
《固体力学学报》
CAS
CSCD
北大核心
2015年第5期444-452,共9页
Chinese Journal of Solid Mechanics
基金
国家自然科学基金项目(51278282)
湖北省教育厅科学技术研究项目(Q20131307)资助
关键词
斜拉索
塔-索-桥面结构
参数振动
频率比
数值仿真
long cable
tower-cable-deck system
coupled vibration
frequency ratio
deck excitation
