dual-layer multiple tuned mass dampers for vibration control of structures

the performance of dual-layer multiple tuned mass dampers (dl-mtmd) with uniformly distributed natural frequencies is investigated. the dl-mtmd consists of one large tuned mass damper (l-tmd) and an arbitrary number of small tuned mass dampers (s-tmd). the primary structure is represented as a single degree-of-freedom system which corresponds to a specific vibration mode to be controlled in a real structure. the response of the structure with dl-mtmd is studied under harmonic excitation acting at the primary main system. the performance criterion used for assessing the optimum parameters and effectiveness of the dl-mtmd is selected as the minimization of the maximum dynamic magnification factor (dmf) of the displacement response of main structure. two dynamic models of the dl-mtmd are proposed in the present study. the model-i consists of s-tmd having the same mass and damping ratio and uniform distribution of natural frequencies. the model-ii consists of s-tmd with same stiffness and equal damping ratio and uniform distribution of natural frequencies. the comparative performance of the two models indicated that the performance of model-ii in comparison with model-i is superior with respect to reduction in the displacement dmf.