Evaluation of Multiple Dual Tuned Mass Dampers for Structures Under Harmonic Ground Acceleration

The multiple dual tuned mass dampers, referred to as the MDTMD, consisting of several units of dual tuned mass dampers (DTMD) are proposed for the first time herein, aimed at the effectiveness and robustness of the system for suppressing the undesirable vibrations of structures under the ground acceleration. The total number of dampers can be arbitrary and their natural frequencies are uniformly distributed. Ten typical types of the MDTMD can be devised by varying the system parameters. Employing the criteria chosen for optimum searching, parametric studies were carried out to evaluate the performance of the MDTMD of Type I-1 for its convenience in manufacturing, in which the larger mass blocks (LMBs) are assumed to have identical stiffness, but unequal masses, and the smaller mass blocks (SMBs) have identical stiffness and damping coefficient, but unequal masses and damping ratios. By adopting the maximum dynamic magnification factor (DMF) for each LMB and SMB used in estimating the stroke, an evaluation is also made for the stroke of the MDTMD. The numerical results indicate that the MDTMD (I-1) can provide better effectiveness and higher robustness in comparison with the dual tuned mass dampers (DTMD) and other MTMD systems of similar complexities. However, the stroke of the MDTMD is greater than that of the DTMD and the stroke of each SMB in the MDTMD is larger than that of the mass blocks (MBs) in the arbitrary integer and odd number based MTMD.