Hydrodynamic characteristics and application of tuned liquid dampers with internal damping devices

Abstract

The hydrodynamic characteristics of rectangular tanks with internal damping devices, including baffles and paddles, are investigated using shaking table tests excited by colored noise. The complex second‐order blind identification method is employed to decouple fluid sloshing responses and to obtain mode shapes. The modal frequency and damping ratio are also identified by the modified Bayesian spectral density approach. The influence of baffle angle, paddle width, liquid depth, and excitation amplitude on the natural frequency and damping ratio of tuned liquid dampers (TLDs) is analyzed. Results show that the natural frequency is reduced due to the added mass produced by the damping devices, and the reduction increases gradually with the increase in the size of the damping devices, indicating that the influence of the added mass should be considered in the design. This result is essentially different from the conclusion of the existing finding that the modal frequency of TLD increases continuously with the increase in the baffle angle. Therefore, the tuning of TLD cannot be realized by rotating the baffles. Moreover, the damping ratio of TLD with paddles shows a nonlinear relationship with the fluid response. The nonlinear empirical model fitted by the test results can predict the damping ratio with high accuracy and can be used in the preliminary design of TLD for the wind‐induced vibration control of super‐tall buildings.