Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, India
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.