Investigation of Tuned Liquid Dampers under Large Amplitude Excitation

Abstract

The behavior of tuned liquid dampers (TLD) was investigated through laboratory experiments and numerical modeling. Large amplitude excitation is the primary focus, as previous research was limited to small amplitude motion. Time histories of the base shear force and water-surface variations were measured by precisely controlled shaking table tests. The results are compared with a numerical model. The random-choice numerical method was used to solve the fully nonlinear shallow-water wave equations. The results suggest that the model captures the underlying physical phenomenon adequately, including wave breaking, for most of the frequency range of interest and over a wide range of amplitude excitation. It was found that the response frequency of tuned liquid dampers increases as excitation amplitude increases, and the TLD behaves as a hardening spring system. To achieve the most robust system, the design frequency for the damper, if it is computed by the linearized water-wave theory, should be set at the value lower than that of the structure response frequency; hence, the actual nonlinear frequency of the damper matches the structural response. It was found that, even if the damper frequency had been mistuned slightly, the TLD always performed favorably; we observed no adverse effect in the wide range of experimental parameters tested in this study.