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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。
Aiming at the large-span steel and CFRP stay cables with viscous dampers, the damping ratios of non-proportional mode shapes of cables based on complex eigenvalues and nonlinear free-decay vibration are compared. It is verified that the complex eigenvalue method is effective in large span The validity of the cable damping evaluation for non-proportional vibration modes of the cable is obtained and the design value of the reasonable viscous damping coefficient of the cable stay is obtained. The results show that the damping effect of viscous damper weakens with the increase of the span of the cable; the damping ratio of the first mode of the cable decreases significantly with the increase of dimensionless parameter λ; The damping effect is better than that of the steel wire. By changing the direction of the damper, the damping characteristics of the cable in-plane and out-of-plane vibration can reach the better condition at the same time. The increase of the cable sag reduces the in-plane vibration of the damper However, the damping effect of the out-of-plane vibration is improved. The natural frequency of the cable is not influenced by the direction of the damper and the viscous damping value.