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

Abstract– 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.