Vibration Suppression in Frame-Structural Tower With Fluid Viscous Dampers

Flexible and skyscraping frame-structural tower is sensitive to dynamic loads, that might oscillate intensely under seismic and wind loads. Thus, vibration suppression system is required and fluid viscous damper (FVD) is implemented to suppress such vibration in this study. The vibration behavior of frame-structural tower with FVD (F-FVD) is investigated by an equivalent model combined with experiment under seismic and wind loads, respectively, and the vibration suppression effect is evaluated by the displacement and energy distribution. The equivalent model of the frame-structural tower with FVD is primarily established, of which FVD is considered through Kelvin model. The parameters of FVD are supplemented to the damping term through a time-dependent damping matrix based in Rayleigh damping, and to the stiffness term through a stiffness matrix based in stiffness-equivalent simply-supported beam. Van der Pol wake oscillator is considered as the wind force term. Several conventional numerical integration methods for solving the equivalent model which belongs to the nonlinear system are compared and Newmark-β algorithm is adopted. The vibration suppression regularity of normalized stiffness coefficient Kr, damping coefficient Cr and velocity exponent α is analyzed via the equivalent model. There is a balance between the stiffness effect and energy dissipation effect of FVD, and the sensitiveness to α depends on excitation and stiffness of F-FVD system. The optimal parameters of fluid viscous damper, Kr = 1.30∼2.0, Cr = 1.65∼3.30 and α = 0.4∼0.8, are obtained eventually. It is indicated that the vibration suppression by fluid viscous damper is effective. And this study can be conducive to vibration suppression design of such flexible and skyscraping frame-structural tower.