OPTIMUM PARAMETERS OF TUNED MASS DAMPERS FOR SEISMIC APPLICATIONS USING CHARGED SYSTEM SEARCH

In this paper, optimum parameters of Tuned Mass Dampers (TMD) are determined
to minimize the dynamic response of multi-story building systems under seismic excitations.
Charged System Search (CSS), as an efficient optimization algorithm, is revised and applied for
tuning passive mass dampers. A MATLAB program is developed for numerical optimization and
time domain simulation. Optimization criteria are the peak values of the first story displacement
with and without TMD, and the transfer function from input ground acceleration to the first story
acceleration response. An alternative formulation is also presented for solving state space
equations. Compared to other population-based meta-heuristics, the charged system search has a
number of advantages distinguishing this algorithm from the others. However, for improving
exploitation (the fine search around a local optimum), it is hybridized with HS that utilizes charged
memory (CM) to speed up its convergence. To ensure good performance of this approach, some
numerical considerations are conducted to verify the effectiveness and feasibility of the presented
approach.