Publications

Abstract : Tuned mass dampers (TMDs) are one of the strategies implemented in the field of structural vibration control. Most researchers have only focused on the control of one specific mode of vibration by idealizing the structure as a single-degree-of-freedom system. From a practical point of view, the use of a single large TMD within a structure would adversely affect the architectural appeal, usable space, and ease of installation. This study introduces a multiple tuned mass damper (MTMD) system, which is simple and more effective than a conventional single TMD system. The system consists of multiple smaller dampers distributed within the structure either uniformly, varying linearly, or based on the judgment of the designer. TMDs tuned to the first, second, and third natural frequencies are used to control vibrations, thus enabling a wider bandwidth of vibration control and attaining remarkable reductions in floor displacements, floor accelerations, and base shear. A MTMD system was investigated for different base excitations, namely harmonic and seismic. A three-degrees-of-freedom frame model and three mass dampers tuned to all three natural frequencies of the system were fabricated. This building model was studied experimentally and analyzed to investigate the effect of harmonic base excitation on structures. Compared with single TMD systems, the performance of the proposed MTMDs system was found to be excellent in controlling displacements. A five-degrees-of-freedom structure was analyzed for seismic excitation to study the effect of two mass dampers tuned to first two natural frequencies with a mass ratio of 5%. The proposed system significantly reduced the displacement, acceleration, and base shear response at the next-higher-order natural frequency beyond the fundamental. The responses of the structures were compared to assess the optimal placement of dampers to attain highest performance. Vibration control by multiple TMDs was found to be more efficient when dampers are strategically placed on the floors, with the maximum amplitude in the mode shapes corresponding to the respective tuning frequencies.