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In this research the behaviour of a one degree of freedom structure controlled by an optimal tuned liquid column damper (TLCD) and subjected to stochastic seismic excitations of high frequency content is studied. Uncertainty is introduced in some system parameters. The influence on the behaviour of the optimal TLCD parameters, on the efficiency measured as reduction of main system displacement and on the root mean square (RMS) displacement of the structure is analysed. An equivalent statistical linearization is performed to include the non-linear nature of the TLCD. The optimal TLCD parameters are the frequency ratio and the pressure drop coefficient. TLCD optimization is performed by minimizing the standard deviation reduction of mainframe displacement. The uncertainty is entered into the mass ratio, length ratio, and head loss coefficient. The behaviour of the efficiency is analysed, measured as a percentage reduction of the displacement when including an optimal TLCD and the RMS of the displacement, before the inclusion of uncertainty in the aforementioned parameters. It is found that the introduction of uncertainty in the period of the structure produces the highest sensitivity in the optimal parameters of the TLCD, the efficiency and the RMS of the displacement of the structure. This occurs mainly in rigid structures and with a small mass ratio. On the other hand, an uncertainty in the mass ratio, and length ratio of the TLCD does not produce variations in the efficiency or in the RMS of displacement of the structure. [ABSTRACT FROM AUTHOR]

This study analyses the efficiency, in reducing the lateral displacement of a structure, under stochastic seismic excitations of low frequency content. The study device is the Tuned Combined Damper (TCD). The objective is to analyze how its efficiency changes when uncertainty is introduced in the design parameters. The TCD is composed of two mass-effect devices, a tuned mass damper (TMD) and a tuned liquid column damper (TLCD). To work with the nonlinear component of the TLCD equation in stochastic analysis, the equivalent statistical linearization technique was used. Uncertainties of ±5 and ±10% are considered. The parameters to which uncertainty was introduced were the length ratio of the TLCD and the mass ratio. As an optimization criterion, the reduction of the standard deviation of the displacement of the main system was considered. The results show that the efficiency of the TCD is maximum when the period of the structure coincides with the predominant period of seismic excitation. On the other hand, there are slight variations in the efficiency of the TCD when an uncertainty of up to 10% is introduced in the mass or length ratio of the TLCD. [ABSTRACT FROM AUTHOR]

This research studies the behavior of the optimal parameters and the efficiency of the Tuned Combined Damper (TCD) in the control of a structure subjected to seismic excitation, when uncertainty is incorporated in the mass ratio and the length ratio. The TCD is a device made up of a tuned liquid column damper (TLCD), and a tuned mass damper (TMD). Seismic excitation is modeled as a stationary type zeromean Gaussian stochastic process. It is considered a seismic excitation with a high frequency content. The equivalent statistical linearization method is used to linearize the nonlinear equation associated with the tuned fluid damper. The sensitivity of the optimal parameters, the tuning ratio and the head loss coefficient of the TLCD, and the tuning and damping ratio of the AMS are analyzed by including an uncertainty in the mass ratio and the length ratio. Reduction of displacement of the main structure is used as optimization criterion. The TCD efficiency and root mean square RMS of the main system displacement are obtained. The results show that the most sensitive parameter is the head loss coefficient, when faced with an uncertainty in the length ratio. It is concluded that the efficiency of the TCD and RMS of displacement of the main structure is insensitive to an uncertainty of less than 10%, both of the mass ratio and the length ratio. [ABSTRACT FROM AUTHOR]