摘要
针对配置粘性阻尼器的大跨度钢和CFRP斜拉索,比较了基于复数特征值和非线性自由衰减振动两种理论得到的拉索非比例振型阻尼比,验证了复数特征值方法在大跨度拉索非比例振型阻尼评估中的有效性,得到了斜拉索合理粘性阻尼系数的设计值。结果表明,粘性阻尼器的阻尼效果随斜拉索跨度的增大而减弱;拉索的第一阶振型阻尼比随无量纲参数λ的增大而显著减小;阻尼器对CFRP拉索的减振效果优于钢索;通过改变阻尼器的方向可使拉索面内及面外振动的阻尼特性同时达到较佳的状态;拉索垂度的增大降低了阻尼器面内振动的减振效果,但提高了面外振动的减振效果;拉索自振频率受阻尼器方向及粘性阻尼值的影响不大。
For long-span stayed cables equipped with oil dampers, the applicability of complex eigenvalue method in evaluating non-proportional modal damping ratios was verified by comparing the damping ratios obtained from complex eigenvalue with those from nonlinear free decaying vibration, The optimum design damper size was also calculated. It was found that 1） the vibration reduction effect of oil dampers weakens with the increase of cable spans; 2） the damping ratios of the first mode significantly decrease with the increase of non-dimensional parameter 2; 3） the vibration of CFRP cables with oil dampers is more weakened than those of steel cables; 4） the optimum modal damping ratios in and out of plane can be obtained by adjusting damper direction; 5） the increase of cable sag reduces the vibration reduction effect of dampers in plane but increase that effect out of plane; 6） the damper size and direction have less influence on natural frequencies of cables.
出处
《工程力学》
EI
CSCD
北大核心
2009年第5期94-101,共8页
Engineering Mechanics
基金
国家自然科学基金项目(50578141)
关键词
斜拉索
振型阻尼比
非比例阻尼
CFRP
复数特征值
非线性振动
stayed cable
modal damping ratio
non-proportional damping
CFRP
complex eigenvalue
nonlinear vibration
