Abstract This study reports a comprehensive performance comparison of two types of widely used dampers, i.e., viscoelastic dampers (VEDs) and viscous dampers (VDs), for multi-mode vibration control of long cables. Cables of three different lengths (334.2 m, 454.1 m and 546.9 m respectively) in the Sutong Bridge were chosen for investigation. The VED is of viscous-shear type and it consists a housing box containing viscous medium and shear plates immersed in the viscous medium. When attached to the cable, the shear plates and the housing are respectively connected to the cable with a clamp and to a support using flange connections. The VD under study is a typical fluid damper which uses two ball joints to respectively connect to the cable and the support. The manufactured dampers were first tested in laboratory for mechanical properties based on which the damper design was adjusted for maximizing multi-mode cable damping effects. The dampers were eventually attached to the respective cable on the bridge for field tests when the bridge was in operation. Field test results show that the VED provides comparable damping effects for all tested modes while the VD provided damping decreases considerably for higher cable modes. For cable modes with frequency approximately ranging from 1.4 Hz to 3.0 Hz their performances are comparable. Comparisons have then been performed between the measurements and analytical analyses based on a model of a shallow cable with a Kelvin-Voigt damper using damper parameters identified from laboratory tests. It is found that for the VEDs theoretical predictions agree well with the measurements suggesting no efficiency loss from damper support or connections while the measured damping ratios provided by the VD are about 33% to 80% of the corresponding theoretical estimates which is probably attributed to the joints required for the VDs. In addition, measurements on damper deformation in the field tests show that the damper for such long cables experiences continuous cyclic deformation with large amplitude and low frequency due to heavy traffic load induced bridge deck deflections. This deformation could cause severe fatigue problems of the damper and its connections and hence needs to be considered in damper design.

中文翻译：

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粘弹性阻尼器多模态缆索振动控制在苏通大桥现场试验对比研究

摘要 本研究报告了两种广泛使用的阻尼器的综合性能比较，即粘弹性阻尼器（VEDs）和粘性阻尼器（VDs），用于长电缆的多模振动控制。选取苏通大桥三种不同长度（分别为334.2 m、454.1 m和546.9 m）的电缆进行调查。VED 是粘性剪切型，它由一个装有粘性介质的外壳和浸入粘性介质中的剪切板组成。当连接到电缆时，剪切板和外壳分别通过夹子连接到电缆和使用法兰连接件连接到支架。所研究的 VD 是一种典型的流体阻尼器，它使用两个球形接头分别连接电缆和支架。制造的阻尼器首先在实验室进行机械性能测试，在此基础上调整阻尼器设计以最大化多模式电缆阻尼效果。当桥梁运行时，阻尼器最终连接到桥梁上的相应电缆以进行现场测试。现场测试结果表明，VED 为所有测试模式提供了可比的阻尼效果，而 VD 提供的阻尼对于更高的电缆模式显着降低。对于频率大约在 1.4 Hz 到 3.0 Hz 之间的电缆模式，它们的性能相当。然后，基于带有 Kelvin-Voigt 阻尼器的浅缆模型，使用从实验室测试中确定的阻尼器参数，在测量和分析分析之间进行了比较。发现对于 VED 的理论预测与测量结果非常吻合，表明阻尼器支撑或连接没有效率损失，而 VD 提供的测量阻尼比约为相应理论估计值的 33% 至 80%，这可能归因于VD 所需的接头。此外，现场试验中阻尼器变形的测量表明，由于大交通载荷引起桥面挠度，这种长电缆的阻尼器经历了大振幅和低频率的连续循环变形。这种变形会导致阻尼器及其连接处出现严重的疲劳问题，因此需要在阻尼器设计中加以考虑。