The hybrid active tuned mass dampers (HATMD)—a new control system—have been proposed to attenuate undesirable oscillations of structures under the ground acceleration. Based on the authors recent exploration, the performance of the active tuned mass damper (ATMD) with the negative normalized acceleration feedback gain factors (NNAFGF) scheme is better than that with the positive NAFGF (PNAFGF) scheme; therefore, the active control forces of the HATMD are generated by combined use of both the NNAFGF and PNAFGF schemes. In the light of the mode-generalized system in the specific vibration mode being controlled (simply referred here to as the structure) and accordingly deduced formulae, the expression then is defined for the dynamic magnification factor (DMF) of the structure furnished with the HATMD. Naturally, the criterion for the optimum searching can be determined as the minimization of the minimum values of the maximum DMF. By resorting to the selected criterion and utilizing a genetic algorithm, the effects of varying the key parameters on the optimum performance of the HATMD have been scrutinized both to arrive at the parameter combinations that make it best work and to make an attempt to shed light on the particular phenomena that for it there may exist. Furthermore, for the purpose of comparison, this study simultaneously investigates the optimum performance of both the ATMD and active–passive tuned mass dampers (APTMD) employing the proposed NNAFGF scheme. It is found in terms of numerical results that the HATMD outperforms both the ATMD and APTMD. Copyright © 2014 John Wiley & Sons, Ltd.

It is widely acknowledged that the tuned mass damper (TMD) is one of the most effective and simplest passive control devices, but its limited control performance is still a troubling problem. In order to surmount the shortage of TMD, the tuned tandem mass dampers (referred herein to as TTMD) have been proposed for mitigating the undesirable oscillation of structures under the ground acceleration. Based on the formulation of the mode-generalized system in the specific vibration mode being controlled, the analytical expression is then derived for the dynamic magnification factor of the structure furnished with a TTMD. The optimum criterion can thereby be defined as minimization of the minimum values of the maximum dynamic magnification factor with a set of optimization variables embedded so as to give full play to the control device potential. The optimization implementation of TTMD is carried out by the MATLAB-based coding and debugging. For the purpose of a mutual authentication to the optimization results, three metaheuristic algorithms, namely, genetic algorithm, particle swarm optimization, and simulated annealing, are concurrently taken into consideration. Results demonstrate that the proposed TTMD endows with the superior stroke performance with respect to TMD.