A tuned liquid damper (TLD), which consists of rigid tanks partially filled by liquid, is a type of passive control devicerelying upon liquid sloshing forces or moments to change the dynamical properties and to dissipate vibrationalenergy of a structure. An analytical non-linear model is proposed for a TLD using rectangular tanks filled with shallowliquid under pitching vibration, utilizing a shallow water wave theory. The model includes the linear damping of thesloshing liquid, which is an important parameter in the study of a TLD as it affects the efficiency of the TLD. Shakingtable experiments were conducted for verification; good agreement between the analytical simulations and the experi-mental results was observed in a small excitation amplitude range. The simulations of TLD-structure interaction by usingthe proposed model show that the TLD can efficiently suppress resonant pitching vibration of a structure. It is also foundthat the effectiveness of a TLD for suppressing the pitching vibration depends not only on the mass of liquid in the TLDbut also on the configuration of the liquid as well as upon the position where the TLD is located. If the configuration ofthe liquid, i.e. the liquid depth and the TLD tank size, is designed suitably, the TLD can have a large suppressing momentand can be very effective even with a small mass of liquid.

A new kind of passive mechanical damper, tuned liquid damper (TLD), is studied that relies upon the motion of shallow liquid in a rigid tank for changingthe dynamic characteristics of a structure and dissipating its vibration energy. Anonlinear model of two-dimensional liquid motion inside a rectangular TLD sub-jected to horizontal motion is developed on the basis of shallow-water wave theory,where the damping of the liquid motion is included semianalytically. Using themodel, the response of a structure with TLD is also computed. The liquid motioninside the TLD under harmonic base excitation and, furthermore, the response ofa single-degree-of-freedom structure with TLD, subjected to harmonic externalforce, are experimentally investigated. The agreement is good between the exper-iment and the prediction.

Tuned Liquid Damper (TLD) utilizing the motion of shallow liquid for absorbing anddissipating the vibrational energy is studied with emphasis on liquid motion. Amathematical model based on the nonlinear shallow water wave theory is presented todescribe the liquid motion in a rectangular tank. Liquid damping is evaluated semi-analytically and is included in the formulation. Mechanical properties of: TLD are alsoexperimentally investigated using the shaking table. It is found that the liquid motion inTLD is strongly nonlinear and reveals a hardening-spring property even under smallexcitation, Good agreements between the simulation and the experimental results areshown when no breaking wave occurs. The model presented in this study is expected toserve as a tool for TLD design.