Analysis of the efficiency of a combined tuned damper with uncertainty in the parameters subject to seismic excitations of low frequency content

Abstract

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.